We found the Xylene out of the recycler is more pure than what is available commercially. We used our recycled xylene for processing, staining but not coverslipping on an automatic celluloid tape coverslipper b/c the recycled xylene distorts the tape. we had both the CBG and the BR in at the same time, did a side by side analysis and the CBG hands down was a better, easier, safer instrument and if not for a tech spilling some xylene on the floor we would still be using it. A great feature of the CBG instrument was that it didn't raise the room temp at all. ( space here being at a premium) 
 
your slide is just drying out. the "blackness" is the dry tissue and stain absorbing rather than reflecting light, cresyl violet being relatively dark. Your tissue won't be ruined and as you notice, just dunk back in xylene and voila- good as new. If you don't want a coverslip(?) you can add a few drops of immersion oil and the slide will look just as nice. Coverslipping is a protective measure though, so why not? Just be careful not to scratch the cell off if you don't cover 'em.
 
I work in a high volume IHC lab and we float 4 micron thick sections on a tap water bath at 45C, pick up on poly-l lysine or aminosilane slides, place label end down in a polyethylene microwaving tray , microwave on high in an 1100 w oven for 3 minutes, cool and procede.For IHC we use heat retrieval on all but 2 of our 120 antibodies.  The timing is different according to your oven and # of slides, and you MUST have a functional carousel tray,(ever see a slide explode?) Our routine lab treats all the routine slides in the same manner with great results. They only use treated slides for certain procedures. 
 

_______________________________________________
Histonet mailing list
Histonet@lists.utsouthwestern.edu
http://lists.utsouthwestern.edu/mailman/listinfo/histonet