Sorry to bump this up with a couple of questions that are relatively trivial compared to what most here are doing replacing whole key assemblies. I have an XP-80 as well and as you probably guessed, had the same problem with the epoxy.
Roland US actually did most of the repair for me and did a very good job replacing the key assembly. However, they didn't really deal with some of the more cosmetic issues and there is still some goop on the exterior of the unit - mostly the metal area right under the keys as well as a little on the top and a lot on the power cord itself (the keyboard was in a gig bag with the cord on top of the keys when the epoxy started leaking and I hadn't taken it out of the bag for an extended period).
I got out the hair dryer and a dry rag after Goo Gone failed to do anything, but am wary of getting water too close to the unit and also a little unsure of the wisdom of heating the rubber(?) power cord to get the goo off. Do I just need to be patient with the warm air? It seems to take quite a while to get small patches warm enough to melt the epoxy.