I don't know if you have an oven available to you, but we bake our slides overnight in the 70 degree oven, and they are fine to file the next day. You can purchase metal slide trays from Cardinal (cat. # M6349-1) or CBG (check their website). Unfortunately, there is the added task of transferring from the cardboard folders to the metal ones, but this way, you won't have thousands of slides drying on your counters. Also, we don't bake the slides over the weekend because they are plenty dry by the time the weekend is over. The metal trays aren't cheap, but over the long term they may be cheaper than buying an expensive mounting media.
Another option to consider if that option is not available to you is to reduce the amount of mounting medium to the very smallest volume necessary to cover the slide. I had to change the volume the machine used when I changed brands.
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