if you use caustic soda use bits of wire round the parts then you can lift them in and out to check them , they may go black but this will polish off with autosol they only need to be in fo a few seconds also have a bucket of cold water handy to dunk them in cause they get hot and also you can use it to rinse your hands if you get some on you , wear goggles and rubber gauntlets and thick clothing and do it outside