Do not smoke, use lanterns or open flames or heaters near oily painting rags, thinner buckets or flammable oil painting materials. Use proper ventilation while oil painting. If the thinner odor is annoying, it is probably dangerous. Odorless thinners are somewhat safer but it's still not a good idea to dry paintings in the same room you sleep in without an exhaust fan. Oil painting is like using spray paint indoors - be careful, it's toxic fumes and flammable. If you paint outdoors, be careful not to pour off used thinner or paint into the grass. It may be toxic to the environment. Recycle your cleaning bucket thinner by letting it stand with a screen to catch the sludge, when it's more or less clean pour it into a fresh jar and store the sludge for disposal. Dispose according to your neighborhood and city's rules for toxic trash. Sometimes if you use very little thinner, soak it up in paper towels and clean with minimal liquid, so that the trash is all ...