Burn off is the most efficient way to remove heavy paint from a metallic object.. It is usually done by a hot air gun, a gas torch or more professionally by a burn off oven in a blast room.

The burn off oven is used for industrial purposes for a process referred to as thermal stripping. However non ferrous metals like aluminum cannot be stripped as this will harm their substrate.
A Burn off oven is a huge enclosure measuring 8'W x 9'H x 10'L and can fit a car. The major advantage of using a burn off oven is that it is safe, inexpensive, quick and effective in removing paint. Paints especially lead based produce toxic chemicals when heated hence the burn off oven protects against these toxic fumes.

After a part has been thermally stripped in the burn off oven, the ash is scrubbed off and if rust removal is needed the part is again blasted off with aluminum oxide.