Engine covers

Hi guys,
I am in the middle of my restoration ('82 A4 ) and am wanting to clean up my engine covers so I can polish them up, ie clutch cover, alternator cover etc.
It appears that someone in it's life time ( or maybe from production? ) has painted all the covers with a silver paint. I have attempted to strip ( with a paint stripper ) this paint off. The top covering of paint is removed to reveal what looks like a sort of rubberized grey coloured coating which is not affected by the stripper. Has anyone else come across this, if so how did you remove it.
I was hoping to do this myself instead of getting it soda/sand blasted.
Any ideas welcome.
Cheers

I had a later model clutch cover with the bigger oil sight glass, I put it on my '79, the chrome was peeling off, so I took it in to a chrome shop and had the chrome removed, when I got it back it was a grey colour, maybe the previous owner removed the chrome and just painted over the grey ?, I got mine polished with fine wet and dry paper and heaps of elbow grease, looks ok now, or with you using a paint stripper will affect the aluminium case and turn it a grey colour, either way bare aluminium will need to be polished or chromed, cheers Pete.