I had some problems over the weekend. apparently the front, drop down door on the UM3 came open and the printer continued to try to print. I wound up with a very large mass of filament all over the #1 Nozzle and up into the head (I should have taken some pictures, it was impressive). In order to remover the filament, I was forced to remove and disassemble the head and use a heat gun to melt the material sufficiently for removal in small bites.
I now have a small problem. Everything is cleaned