ORIGINAL: mpriestley
So I tried the nail polish remover. Main ingredient was acetone.
it did make it feel very clean, however did not change the finish. maybe the finish is normal but it looks like the color of a light grey primer or maybe a powder coat.
So far, paint remover, denatured alcohal, acetone, soap, silver polish, mothers allum. polish and one other polish and no change to the color or finish.
when I sand it with a few different grits it seems to come to life and I can get the allum look (ie polish) that I am used.
I guess I dont need to worry about it if the finish is truly clean, all should stick well...
mpriestly,
Not sure if you have solved your problem yet, but this may help. Are you referring to the printing side of the plate, or the bare aluminium side? If the printer has "cleaned" the printing surface, then you are half way there. I think your problem is that lithoplates are anodised. Anodising is a hard oxide "film" over the surface of the aluminium, which is very hard. You need to remove this "film" before any polishing will be successful. Try soaking the sheet in Draino for about 45 minutes, or another producthat contains Sodium Hydroxide, like oven cleaner. This will etch away the anodised surface, leaving the aluminium intact. You will initially have a dull grey surface, but it will take a polish much better than before.
See here:
http://www.secondchancegarage.com/public/665.cfm
Regards,
James.