I have a nice sharp gasket scraper in my toolbag just for special situations like this one. It would make short work of that caulk hack in no time.
On a side note: I've been using this stuff called Geocel 2300. It's a tripolymer sealant that works friggin great. So well in fact, that I'll never touch another tube of caulk till I die unless I'm just tossing it in the garbage . It'll literally adhere to anything and it lasts forever. It's avail in a ton of colors and clear.(The clear is just that, clear like glass). You use mineral spirits and not spit or water on your finger to tool it out and the end result is pretty strong, but it won't crack from movement or vibration. Stretch on it is like 500%.
Pretty good stuff if any of you have a problem job where caulk keeps leaking thru, or needs to be replaced once and a while. This stuff will fix the problem. It's about 7 bucks a tube from construction supply places like lumberyards and so forth.
Sometimes roofers don't know what the h*ll they are caulking. Had issues with some 16 year old Carrier RTU's that constantly started leaking. Problem was not with the units themselves but with the seal between the unit and curb. Water would run down the unit, down along rails and seep through the dry-rotted seal on the curb. Could only reseal what you could get to, not directly behind the rails unless unit was lifted off of curb and new sealing material installed. Roofers have the right idea, but sometimes do not understand how the covers have the angle formed to keep water out. And cutting the crap they use is sometimes a complete hassle--especially if they used roof muck.