I would like to describe a problem that we have been experiencing in our lab. 
 The problem that we are experiencing is with our Leica CV5000 
(auto-coverslipper):

*  No bubbles are seen in slides after coverslip.

*  After a day or two, a huge air bubble (gap) is formed, surrounding the 
tissue specimen.

*  We have increased the volume of the mounting media, but this causes an 
overflow of media on top of the cover glass.

Question:  What is your current use of mounting media, and your use of 
clearing agent for your staining?