I address the mold problem in the Hot Glue page at my web site.
If you use glue bottles, the mold problem is non-existent if you use
fresh glue bottles and refrigerate them when not in use.

If you use older used-before bottles, there is some mold but nothing
close to what is in a pot liner.  The bottles solve several other glue
problems.  Check out the "Technical tips" page and the "Hide glue" page
found there at the web site below.

D.L. Bullock    St. Louis
http://www.thepianoworld.com/