What is the strongest type of paint remover?

Paint removers that contain methylene chloride are very effective at stripping and dissolving up to 30 coats of alkyd or latex paint at once -- this kind of paint remover is called a solvent stripper. Other options beyond solvent strippers are caustic or biochemical solutions.

Paint removers that contain methylene chloride can be toxic. It is important to work in a ventilated area if using methylene chloride to avoid possible toxicity and damage to the liver and brain. New alternatives have been developed as of 2015, most often marketed as non-methylene chloride paint remover. They are N-methyl-2-pyrrolidone (NMP) in combination with dibasic esters (DBE).