[pugs]

If you had a broken tap or drill in an aluminum part (or brass or other non steel) you can use Alum, aluminum sulfate (dissolved in water) to dissolve the steel and not the aluminum, it's slow going. Nitric acid works faster but is not always easy to come by.

If you have taps or drills that are plugged up with aluminum you can use Red Devil Lye (dissolved in water) to dissolve the aluminum and not harm the tap.