Hi Ann,
    50% acetone 50% xylene works fine. As for antigenicity, I always tell whomever sends us these specimen that ideally we want a tissue block, if not then an unstained slide, as a last resort a stained slide. You never know how a slide was handled before you get it.
Usually they are microwaved, cut thicker than IHC slides should be, floated on a waterbath with albumin or gelatin the list goes on. Usually there is no problem with this, but it is a possible source of error.
    By the way, if you aren't doing heat induced epitope retrieval, I tried something REALLY cool the other day. Someone cut through a block and there was no tissue to do an IHC stain the doctor really wanted. So I  took one of the original 2 H&E slides, and since he
needed the H&E on both slides and there were two sections on the slide I had, I cut and removed the coverslip from 1/2 the slide and left the top section intact. Then did an IHC stain (PSA) on the bottom section. It came out beautiful, and saved the patient from being
rebiopsied. If you run out of tissue and want to retain H&E and still do IHC this can be done with out needing to do a liftoff and potentially loosing more tissue.
Amos Brooks

ANN MARUSKA wrote:

> Dear Histonetters,
> For those of you who do IHC stains and get slides that have been previously stained e.g. H&E, how do you get the coverslip film off the slides?  I know there is a quick method by placing the slides in acetone, but does this affect the antigenicity of those slides?
> Right now I soak them in Xylene, but it takes days to get the film unglued.  Glass coverslips come off rather quickly in xylene, it's just the film coverslip that takes forever.
> Thanks for whatever info you can share.
> Ann Maruska
> Fairview-University Med Ctr
> Mpls.  MN  55454
> amarusk1@fairview.org