all the worms are typical, brown, black, red, (sold under "monkey grip/Slime/other" generic company kits) and they all are coated in a compatible rubber, which does completely melt and bond them all, to the tire rubber, when the cement is applied LIBERALLY.. and I mean "slathered" on the rope...
my normal progression, is to first, attach my air pump, and begin airing up the flattened tire while I prepare the rope plug, with all the stuff sitting there on the ground on a rag... I fully coat the "rasp" with glue, and insert it, and push/pull 2 or 3 times, then do not withdraw it, while it's goobered with glue, it is sealing...then I squirt the cement on the worm, goober it up good, if it' a small nail hole (like a brad/or 8 penny nail) I make sure the "excess" inside the tire is "short", like 1/2" long, as a doubled up rope (bent in the middle) is a bit excessive for a "small" hole, or even a normal drywall screw... then I pull the rasp out, jam the plugger tool and plug in, twist and withdraw the tool.... it's sealed baby...
if the hole is larger, like a 16 penny spike, or something about 1/8' diameter(that pierced the tire), I'll do the doubled over full worm, with both ends ending up outside the tire tread..
like I noted, I ran a 1/8" drill bit into the tet tire, so a lot of rubber was actually removed, not just displaced like in a "puncture" scenario.
I've installed plugs in various car tires, at work and on the road for people, that jammed a dry plug in, and expected it to work... all I could say to them ALL, was "can't you read directions on the kit?
?"
can't fix those people... they made velcro tennis shoes especially for them...
once you open the tube of glue, might a well toss it out on your way home, when you buy replacement plugs and a fresh tube of glue, and never open them till needed.. I buy Monkey Grip tire cement in 6 oz cans, and keep them sealed.