Short answer: Don't scrape Highway 17 tar with a razor blade or fingernail, and skip the WD-40. Soften it with a dedicated tar and adhesive remover, let it dwell 2 to 3 minutes, then lift it with a clean microfiber towel using light pressure instead of scrubbing. Wash within a few days of a summit run — tar that bakes in for a week or two bonds harder and is more likely to leave a mark if you try to force it off. Right now, VTA's active widening work near Lark Avenue means more loose tar and fresh asphalt than a typical year, so Los Gatos commuters are seeing it more often. A wash and fresh sealant handles ordinary tar; a dulled or etched patch from tar that sat too long needs polishing, which is honestly outside what we offer.
If your commute in or out of Los Gatos runs south on Highway 17 toward the summit, you've probably noticed more of it lately: fine black flecks on the front bumper and rocker panels that weren't there a few months ago. That's not a coincidence. VTA's Route 17 Corridor Congestion Relief Project — an $11.3 million effort to widen the stretch between Lark Avenue and the Highway 9 interchange — is actively under construction right now, and active roadwork disturbs old asphalt and lays fresh material that hasn't fully cured. Both throw more loose tar and aggregate onto the cars behind them than a section of highway that's been sitting untouched for years.
A Bad Stretch of Road at a Bad Time
Los Gatos sits at the exact spot where the valley floor gives way to the Santa Cruz Mountains, so unlike a driver who only ever sees flat surface streets, almost every Los Gatos commuter crosses the Highway 17 grade multiple times a week — whether the destination is Scotts Valley for work, the summit for a hike, or just the Lark Avenue on-ramp to get to 85. Caltrans has also had recurring maintenance closures on this same stretch through 2026, on top of the VTA widening. The combined effect is more contact with soft, disturbed, or freshly laid asphalt than most South Bay cities ever deal with.
The Removal Steps We Actually Use
The mistake we see most often is someone trying to pick tar off dry with a fingernail in a Safeway parking lot on North Santa Cruz Avenue. Dry rubbing drags whatever grit is mixed into the tar across the clear coat, which is how a small spot turns into a fine scratch. The order matters more than which specific product is in your hand.
- Rinse the panel first. Plain water clears loose road dust so the next step isn't grinding grit into the tar.
- Apply a dedicated tar and adhesive remover and let it sit 2 to 3 minutes. This dwell time is what actually breaks the bond — most people skip it and go straight to scrubbing, which is the wrong order.
- Lift with a clean microfiber towel, working from the outside edge of the spot inward, light pressure only.
- Rinse and towel-dry immediately. Los Gatos sits on the same hard Santa Clara Valley water as the rest of the South Bay, and a spot left to air-dry just trades one problem for another.
Skip the razor blade and the WD-40. A blade cuts straight through clear coat if the tar underneath hasn't fully released, and WD-40 is a petroleum solvent that isn't made for paint — it can haze certain trim and leaves an oily film that just collects more dust. Use a purpose-made tar remover instead.
| Method | What actually happens | Verdict |
|---|---|---|
| Fingernail or razor scrape | Cuts into clear coat that hasn't been softened first | The most common way people mark their own paint |
| WD-40 or a household degreaser | Not formulated for clear coat; hazes trim, leaves residue | Skip it entirely |
| Touchless car wash alone | Water pressure and soap don't dissolve bonded tar | Won't remove it, but won't hurt anything either |
| Tar remover, dwelled, lifted with microfiber | Chemically dissolves the bond before any contact | What actually works, and what we use |
| Baked on for weeks over the summit | Tar etches or stains into the clear coat over time | Beyond a wash — needs polishing we don't offer |
Redwood Sap Compounds It in the Almond Grove and Blossom Hill Foothills
Tar isn't the only thing landing on a Los Gatos car. The Almond Grove — one of the town's oldest neighborhoods, its Victorian homes and picket fences a few blocks off downtown Santa Cruz Avenue — sits under mature tree canopy, and the ranch homes up in Blossom Hill Manor and the Alta Vista and Belgatos foothills toward Lexington Reservoir see even heavier redwood and oak cover. Sap and tar need different treatment: sap is a plant resin that lifts with an isopropyl alcohol dab while it's fresh, and using a tar remover on sap (or the reverse) just spreads the spot around instead of dissolving it. A car that's picked up both after a summit run needs to be treated as two separate problems, not one pass with one product.
If you're not sure which one you're looking at: tar is glossy black and slightly soft to a fingernail-adjacent touch test; sap is more amber or clear and tackier, especially fresh. When in doubt, treat the spot gently with plain water first and let us sort out the rest at your next detail rather than guessing with a solvent.
Los Gatos Logistics: Downtown Lofts vs. Foothill Driveways
Most of Los Gatos outside the immediate downtown core — Almond Grove, Blossom Hill Manor, and the foothill streets near Vasona Lake County Park — is single-family homes with a driveway and an outdoor tap, which is all mobile detailing needs. We bring every product and tool ourselves; we just need your spigot and a power outlet rather than carrying a water tank. Downtown near Santa Cruz Avenue and North Santa Cruz Boulevard is a different story — a lot of that housing is lofts and apartments above the shops, relying on street parking with no outdoor tap available. If that's your situation, tell us when you book and we'll set up a drop-off at our Santa Clara shop instead, about 15 to 20 minutes away depending on the Lark Avenue on-ramp traffic.
When It's Beyond a Wash
If a panel already shows a dull, slightly hazed patch where tar sat for a couple of weeks, a full exterior wash with clay bar decontamination lifts everything that's still liftable, and a fresh sealant leaves the surface smoother so the next tar spot releases easier. What clay and sealant won't do is restore a clear coat that's already been microscopically etched by tar that sat too long — that's a machine polishing job to level the surface back out, and XN doesn't offer machine buffing or abrasive paint restoration. We'll tell you plainly if that's what you're looking at rather than take the job and let you down.
Keeping It From Coming Back
You can't avoid Highway 17 if it's your route out of town, and you can't control VTA's construction timeline. What you can control is the gap between a tar-picking drive and your next wash. Rinse within a few days of a summit crossing rather than letting a couple of weeks bake it in, and keep a sealant current — it changes how tar releases, not whether it lands. Our detailing frequency guide breaks down the cadence difference between a mountain commute and a car that stays on the valley floor, and if you're crossing the grade most days, a monthly membership usually pencils out better than one-off details every few months. For sap specifically, our Menlo Park sap removal guide covers the alcohol-dab technique in more depth. If you're weighing mobile against a drop-off, see our mobile detailing vs. car wash comparison, and for full pricing by package, see what detailing costs in the Bay Area.
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The products we actually use
Tar removal starts with a plain water rinse, never a straight scrub. Once the spot is soft, we lift it with a dedicated tar and adhesive remover — not a household solvent — using a clean microfiber towel and light pressure. For the wash itself we use a pH-neutral Chemical Guys shampoo with two buckets and grit guards, so grit from the road never gets reintroduced to the paint. We finish with a Meguiar's or Gyeon paint sealant that holds up for roughly three months, giving the clear coat a smoother surface for the next round of Highway 17 tar to fail to stick to. That sealant is a polymer layer, not a multi-year coating — we don't sell one, and if a clear coat is already dulled from tar that sat too long, sealant won't undo that. Leveling a damaged clear coat back out means machine polishing, which is outside what XN offers, and we'd rather say so upfront.
Interiors get Meguiar's leather conditioner and Chemical Guys fabric cleaner where needed, and we bring all of it to you. What we need on site is an outdoor tap and a power outlet — no tap, no problem, just bring the car to Santa Clara instead.
Frequently Asked Questions
Why is Highway 17 tar such a problem for Los Gatos cars specifically?
Los Gatos sits right where Highway 17 leaves the valley floor and starts climbing into the Santa Cruz Mountains, so almost every local driver crosses the same stretch of pavement near Lark Avenue and the Highway 9 interchange multiple times a week. VTA's Route 17 Corridor Congestion Relief Project is actively widening that exact section right now, which means more fresh asphalt, more loose chip-seal aggregate, and more construction-zone dust in the mix than a typical year.
Is the tar worse right now because of the construction?
Yes. Active roadwork disturbs existing asphalt and lays down fresh material that hasn't fully cured, and both throw more loose tar and aggregate onto following traffic than a stretch of road that's been sitting untouched for years. Cars that cross the Lark Avenue to Highway 9 section daily are picking up more of it than usual until the project wraps.
Can I use WD-40 or a razor blade to get tar off my car?
Skip both. WD-40 is a petroleum solvent that isn't formulated for clear coat and can haze plastic trim, and a razor blade or fingernail dragged across tar that hasn't fully released can cut straight through the coating underneath. A dedicated tar and adhesive remover breaks the bond chemically instead, which is the safer route.
How is redwood sap different from Highway 17 tar, and do I need to treat them differently?
Yes. Tar is a petroleum product that needs a dedicated tar and adhesive remover to dissolve; sap is a plant resin that responds better to isopropyl alcohol on a fresh spot. Using the wrong product on either just spreads it around instead of lifting it. If a car has picked up both after a Highway 17 drive through the Almond Grove or Blossom Hill foothills, they need to be treated as two separate spots, not one pass with one product.
I live downtown near Santa Cruz Avenue with no driveway — can you still detail my car?
Yes, but it depends on what's available on site. Mobile detailing needs an outdoor water tap and a power outlet; most of downtown's lofts and apartments along Santa Cruz Avenue and North Santa Cruz Boulevard rely on street parking without either. If that's your situation, drop the car off at our Santa Clara shop instead, about 15 to 20 minutes away.
My car has a dull, hazy patch where old tar sat for weeks — can you fix that?
We want to be straight with you rather than take the job and disappoint you. A dulled or hazed patch from tar that sat too long usually means the clear coat has been microscopically etched, and leveling that back out is a machine polishing job. XN doesn't offer machine buffing or abrasive paint restoration. What we can do is a full decontamination wash with clay bar to lift everything that will still come off, and a fresh sealant so it stops getting worse.
Will a paint sealant stop tar from sticking in the first place?
It won't stop tar from landing on the car, but it changes how it releases. A fresh sealant leaves the clear coat smoother and less porous, so tar sits on the surface instead of bonding into it, and wipes off with less product and less agitation. It still needs to come off within a reasonable window — a sealant isn't immunity.
How often should a Highway 17 commuter get their car detailed?
More often than a car that only sees local Los Gatos streets. We generally recommend a full detail with a fresh sealant every two to three months for a daily Highway 17 commuter, versus three to four months for a car that stays on the valley floor, since the sealant is what's actually doing the work of releasing tar between washes.
Book a Tar & Grime Wash in Los Gatos
Mobile to Almond Grove, Blossom Hill, and the foothills — or drop off at our Santa Clara shop, 15 to 20 minutes away.
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