I've been using Gunslick in my AR's, Mini's, M1 carbines and Garand for several years and never had a problem. I think that the pressure would blow out any congealed Gunslick out of the port anyway. Are you sure that the problem wasn't due to something else?
I use the foam then follow with dry patches then finally with Ed's Red until the patches are clean. I rarely completely disassemble them.