Mike,

You might try an establish where you think the cross contamination is
coming from, if you can.

Always make sure your water bath is cleaned with a Kimwipe between each
block that you cut. I try an use dist water in my water bath also.

When you are staining check and make sure you solutions are changed on a
regular basis. Some stains do grow things. I always change my solutions at
the end of a days work. Maybe not all, but at least the ones that are the
dirtiest.

Usually cross contamination is either in the water bath or while embedding.
It is good to try and keep your embedding area clean also.

Mari Ann Mailhiot BA HT
Applications Specialist
Technical Assistance Center
Leica Microsystems
800 248 0123