What is the proper way to clean a paintbrush and metal pan with KleanStrip paint thinner?
When I use oil based products I use disposable pan liners so cleanup means let it dry-up and throw it away. To clean brushes I use a brush spinner to remove as much material as possible. I swish the brush in a container of mineral spirits and brush a piece of dry cardboard to get out some more of the urethane. Finally I soak the brush for a couple of days in a covered glass jar that has just enough mineral spirits to cover the bristles. After everything is clean I set the mineral spirits filled container in the sun uncovered until it evaporates. I would not dump it on the ground! If you cannot find a way to dispose of it contact your municipal public works dept. Most cities have an annual hazardous waste drop-off.