Hi everyone, I have searched all over but as far as I can see there isn't a thread on this topic...

I have a couple of spare barrels lyiong around from an old seized engine. I'd like to get them cleaned up to see if they will be usable again.

There is piston material scraped on to the inner surface, what is the best way to clean this off? Can it be cleaned off without causing damage?

I also have some heads with detonation and another that has had a bit of ring or something leave a couple of dents. At what level do these become unusable or at least 'you should really just get new ones'?

Cheers for the help.