[buster73]

One of my best investments was a 10 gallon parts washer with a good degreaser fluid. For heavy oil/carbon residue oven-cleaner does a good job, but with alloy parts you have to be careful regarding soaking time so you won´t damage the surface.

I also use a small sand blasting cabinet for soda blasting and glass bead blasting where necessary. With some time and efforts parts will look like new.