Woolwax Black Aerosol Undercoating Spray (12 oz, 6-pack)

Amazon verified-purchase reviewers in Michigan describe buying 6-packs on a monthly cycle for daily-driver trucks — consistent with annual or more frequent reapplication in heavy salt-belt environments. Community consensus across BITOG rustproofing threads is that Woolwax is a thick lanolin-based formula suited to annual touch-up cycles; it performs at least as long as Fluid Film on exposed surfaces, and some BITOG members specifically prefer it for exposed undercarriage panels over Fluid Film for cavity injection. No multi-year skip-reapplication claims are backed by independent community evidence.

SDS §9 for the WOOLWAX HV base formula states VOC = 0 lb/gal and 0 g/L. The aerosol propellant is not disclosed (trade secret per SDS §3), so the total-can VOC figure including propellant is unconfirmed. The base formula itself — the woolgrease and petroleum sulfonate active — carries zero VOC per SDS.

SDS §2 carries no inhalation H-codes (no H335 respiratory irritation, no H330 or H331 inhalation toxicity). The DANGER signal word is from H222 (flammable aerosol) and H229 (pressurized container), not from respiratory hazards. SDS §8 specifies respiratory protection when ventilation is inadequate. For overhead underbody application in an open garage with the door up or outdoor application, the inhalation exposure pathway is low. In a sealed garage with no airflow, respiratory protection and ventilation are indicated per SDS §8.

The lanolin-based (woolgrease) formula is a penetrating, creeping product designed to work on surfaces with light-to-moderate existing rust — it absorbs into surface oxide, displaces moisture, and forms a barrier that slows continued corrosion. It does not chemically convert or neutralize iron oxide. For structurally compromised or heavily perforated metal, a rust converter or encapsulator followed by mechanical repair is the correct first step before any undercoating.

The base formula is the same woolgrease and petroleum sulfonate chemistry as the Woolwax HV brush-on product — the manufacturer publishes a single SDS covering both. The aerosol adds a flammable propellant (trade secret) that accounts for the DANGER signal word, the H222/H229 classification, and the pressurized-container warning. The aerosol form delivers a lighter film per pass; the brush-on HV is higher-viscosity for saturating cavities and seams.