I can get the orange warning label off the side of the factory magazines, but that glue is something else. Tried good old fashioned elbow grease and alcohol so far, and all it does is goop up, spread out, and redistribute.
WD-40 or pretty much any spray lube. I bought a PC9 off Gunbroker a couple of years back. Jammed real back. Found theat the PO had wrapped the bolt counterweight with duct tape to get rid of the 'clunk'. The adhesive had gummed up the whole forestock channel.
Less than 5 minutes with WD & it was good as new.
edit to add; most of that five minutes was pulling off the tape. Residue removal less than a minute. :lol: