Paint Thinners Illegal in Garbage & Drains Hazardous Waste FREE Used Oil Filter Exchange May 10, 2025 Saturday, May 10, 2025 More Info Get Reminder 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 asĀ Household Hazardous Waste (HHW).