Paint Thinners Illegal in Garbage & Drains Hazardous Waste FREE Household Hazardous Waste (HHW) and Mattress Collection Event (Richmond, CA) – ONE DAY ONLY! Saturday, September 24, 2022 More Info Get Reminder Residents may drop-off paints & solvents at the West County HHW Collection Facility. Solvents, as well as nonempty aerosol solvent cans are banned from the trash. Never Dump Down the Drain Paint thinner is highly toxic and should never be dumped down the drain, in order to avoid contaminating waterways. Instead, dispose of as Household Hazardous Waste (HHW).