re: Stinky screwdriver and cure for the mange

BTW, if you don't see any fizzing from the H2O2 when you pour it, especially if you pour it in a sink or something that needs to be cleaned, it has probably lost its effectiveness though it won't hurt anything to try it.  Once it has been opened, it usually goes bad within about 6 months and a max of about 3 years unopened.