I tried a search but didn't find an answer. I am 'overhauling' a small V-6 and after mic-ing the bores & pistons, found that I can re-use the pistons. What is the best way to clean them (on the bench)? The manuals that I have all say "do not use a wire brush to clean any part of the piston". I have had them soaking in my solvent tank for 2 days now and that has not had any effect. The solvent that is available here is not what it used to be.

 

I used some Easy-Off oven cleaner and it took the carbon off, but it also caused the pistons to scale, so it probably did more harm than a wire brush.
I can relate to the solvents. The stuff I put in my parts washer wont cut dust. I bought a kitty litter pan and a couple of gallons of kerosene and clean up everything that way.
I think that "don't use a wire brush anywhere on a piston" is a load of crap anyway. Steel wire-yes. I have a fine wire brass wheel on my bench grinder and it doesn't seem to hurt aluminum at all. Stay above the top compression ring and I guarantee no ill effects and it will make them look like new.
If the pistons are off the rods, you can put them in the dishwasher while your wife's not looking and clean up a lot of stuff off them that way. (The rods will surface rust).

 

Wire wheel them, they don't need to be polished just get rid of all the heavy carbon.

 

Did you try MEK by chance? (Methel-ethel Keytone, I think) It's available at Home depot in the paint section. Just don't get it on your hands, clothes, or anything plastic.

I also second the kerosene trick, and found that if you add a can of seafoam or GM top engine cleaner to it it helps as well.

 

Thanx for the tips guys. I finally succumbed to using my wire wheel - just to get the carbon off - and then set them in Purple Power for a bit. That stuff works a whole lot better than my solvent! Anyway, they came out good and clean and don't appear to have suffered any from the wire wheel.