CRC Knock'er Loose Penetrating Solvent
Priced as of May 30, 2026
4.5(51 ratings)Buy on AmazonSaved to your guest loadout. Sign up to also save to your Cabinet (consumables) or Kit (tools you own).
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Prices may varySerious hazard — read before use
The manufacturer's Safety Data Sheet classifies this product with one or more GHS Category 1 health hazards — the most severe tier. The hazard statements in quotes below are the verbatim GHS language from the SDS, as required by OSHA's Hazard Communication Standard. The line under each statement translates the GHS classification into plain language.
- H304 “May be fatal if swallowed and enters airways.”
GHS Category 1 aspiration toxicity — thin, oily liquids can slip into the lungs if swallowed, causing chemical pneumonia.
If swallowed, inhaled, or splashed in eyes:
Call Poison Control immediately at 1-800-222-1222 (US, 24/7, free) and have the product container with you. Poison Control's standing guidance is to not induce vomiting after chemical exposure; they will direct first-aid steps based on the specific product.
About this product's hazards. This product's Safety Data Sheet uses signal word danger. Read the manufacturer's SDS and follow all safety instructions before use. CarCareTruth ratings translate the manufacturer's safety sheet. They do not replace the SDS or substitute for a hazard assessment specific to your task.
Health score is for adult use as intended, per the manufacturer's SDS. It does not model child ingestion, accidental spill cleanup, or off-label use. See the safety panel below for full hazard classification, and /disclaimer for the full editorial scope.
From the Safety Data Sheet
Full SDS ↗ (rev. 2021-03-02)GHS hazard codes are quoted from the manufacturer’s Safety Data Sheet. PPE tiers below translate those codes and the listed ingredient chemistry; they are not CarCareTruth recommendations.
EyesRecommendedMfr. SDS §8 · 29 CFR 1910.133(a)(1) · GHS H319SkinRecommendedMfr. SDS §8 · 29 CFR 1910.138(a) · GHS H315LungsSituationalMfr. SDS §8 · 29 CFR 1910.1200(f) · GHS H304Ventilation—No PPE in published sourcesShow details for all categories ▾Hide details ▴
From the manufacturer’s Safety Data Sheet, Section 8
“SDS §2 classifies Eye Irritation Category 2A (H319) at the mixture level. Aerosol mist near face level is the primary exposure pathway.”
— CRC
U.S. regulatory standard
29 CFR 1910.133(a)(1)
“The employer shall ensure that each affected employee uses appropriate eye or face protection when exposed to eye or face hazards from… liquid chemicals…”
ANSI Z87.1 (incorporated via §1910.6)
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
From the manufacturer’s Safety Data Sheet, Section 8
“SDS §2 classifies Skin Sensitizer Category 1A (H317) and Skin Irritation Category 2 (H315) at the mixture level. The pine-derived terpene fraction (turpentine, pine oil, alpha-/beta-pinene) is the documented sensitizer driver.”
— CRC
U.S. regulatory standard
29 CFR 1910.138(a)
“appropriate hand protection when employees' hands are exposed to hazards such as those from… chemicals which produce an adverse effect on the skin or eyes…”
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
From the manufacturer’s Safety Data Sheet, Section 8
“H335 (respiratory irritation) is absent from SDS §2 mixture classification, and §11 explicitly states the product is not a respiratory sensitizer. The aerosol mist itself is the inhalation trigger in enclosed or poorly ventilated spaces.”
— CRC
U.S. regulatory standard
29 CFR 1910.1200(f); 1910.132(d)
“The employer shall assess the workplace to determine if hazards are present, or are likely to be present, which necessitate the use of personal protective equipment.”
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
No PPE specified in published sources for ventilation. Absence does not imply “not needed” — consult the full Safety Data Sheet.
PPE tiers translate the manufacturer’s SDS and U.S. regulatory standards. Not professional safety advice. How we report safety.
The Podium · Top 3 in Penetrating Oil / Multi-Purpose Lubricant
See the full ranking →This product ranks #14 of 14 in Penetrating Oil / Multi-Purpose Lubricant.Three above it ↓
CarCareTruth's Analysis
Last reviewed May 30, 2026
TL;DR DANGER-rated aerosol with a confirmed Prop 65 warning. It can be harmful if swallowed and gets into the lungs, so do not induce vomiting if ingested. Wear nitrile gloves and safety glasses, and use outdoors or with ventilation. Community signal on performance is thin (51 Amazon reviews at 4.5 stars).
What it is and how it performs
CRC Knock'er Loose is an aerosol penetrant for freeing seized or rusted fasteners. Spray onto the fastener with the straw, let it wick in for roughly 5 to 15 minutes on light-to-moderate rust, then try the bolt; heavy rust typically needs a second coat. With only 51 Amazon reviews and no head-to-head comparisons against PB Blaster or Kroil located, penetration anchors at category median. A light residual film from the fatty-acid additive offers modest short-term re-seizure protection.
Who should buy this — and who should skip it
A reasonable choice for an owner with a one-off seized fastener who already keeps nitrile gloves and safety glasses in the garage and works outdoors. The skin-sensitizer classification at the mixture level is a chemistry trade-off frequent users may want to weigh against alternatives without H317, and lower-VOC pump-spray alternatives reduce cumulative inhalation exposure for regular use.
Safety and environmental impact
Rated DANGER from health classifications at the mixture level: aspiration hazard if swallowed, skin sensitizer, skin irritant, and eye irritant. Wear nitrile gloves and safety glasses; aerosol mist in enclosed spaces is the inhalation trigger, so use outdoors or with ventilation. Do not induce vomiting if ingested; seek medical attention. Prop 65 warning is confirmed in SDS §15 for trace petroleum-distillate impurities. Environmental: multiple aquatic-toxic ingredients, one bioaccumulative fatty-acid additive (oleic acid), and total VOC above 550 g/L; CARB-compliant in all 50 states under the Penetrant category.
Frequently asked questions
Is CRC Knock'er Loose Penetrating Solvent safe to use?▾
The Safety Data Sheet for CRC Knock'er Loose Penetrating Solvent carries a DANGER signal word, with classified hazards including H223 (flammable aerosol); H229 (pressurized container: may burst if heated); H315 (causes skin irritation). The Amazon listing also carries a California Prop 65 warning. See the PPE breakdown above for use-case-specific guidance translated from the SDS hazard codes.
How does CRC Knock'er Loose Penetrating Solvent score on CarCareTruth?▾
CarCareTruth scores CRC Knock'er Loose Penetrating Solvent at 4.6 out of 10 on the composite CCT score, with a health sub-score of 1.0/10. The CCT score blends real-world effectiveness, ingredient health impact pulled from the manufacturer's safety sheet, and environmental footprint against a published category rubric. See the methodology link on this page for the full scoring breakdown.
What's in CRC Knock'er Loose Penetrating Solvent?▾
Per the Safety Data Sheet ingredient disclosure: SDS §3 (Version 02, rev. 2021-03-02): Distillates (petroleum), hydrotreated middle (CAS 64742-46-7) 40–50%; Dipropylene glycol methyl ether acetate (CAS 88917-22-0) 5–10%; Turpentine oil (CAS 8006-64-2) 5–10%; 2,6-Dimethyl-4-heptanone (CAS 108-83-8) 3–5%; Pine oil (CAS 8002-09-3) 3–5%; alpha-Pinene (CAS 80-56-8) 1–3%; Carbon dioxide (CAS 124-38-9) 1–3%; Distillates (petroleum), hydrotreated light (CAS 64742-47-8) 1–3%; Naphtha (petroleum), hydrotreated hea…
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