A stiff piece of tape is all you need. Feed the tape in and roll the film backwards with it a bit. You have to kind of rewind until you feel it "pop" around the exit ramp, then put the tape in. I even had a specific tape dispenser with a metal tongue to help feed into the canister when I used to work a 1-hour photo machine at a Walgreens.
I've had to do it at home or on the fly more than once. Tape will work there as well, assuming you can feed it past the opening (maybe fold it over itself for a couple of milimeters?). It takes a little practice and finesse, but it's the safest way ... meaning you don't get nasty chemicals on your tongue!
It was a fine skill to learn. I had to learn it. You have to rewind the canister and pull more tape in sometimes (cover more surface area, create more friction) and sometimes you just had to rip the bas.... er... the "sucker" right out if the leader was catching on the inside of the ramp. It might take a few minutes of solid concentration to get it done, but you could do it.
I just used an unexposed strip of photo print paper cut to fit into canister applied plenty of spit,then rolled canister cog clockwise a bit until paper fed into canister the pulled out the leader.It took a couple attempts but finally worked,be patient.It save me a 36 exp. roll.YIPPEEE!!!!!!
In ye oldene dayz we would use the same approach as with a leader retriever; but we would take a fresh roll of film, wet the the leader on both sides by sticking it in the mouth, then push it in. Turning the problem film tight in the cartridge to make contact with the wet leader, waiting a coupla seconds, then pulling out. You would be amazed how often it would work, with most films, and with most sources of spit.
john, hats off! a baby dinousaur myself, yet i never heard of this one. will save me precious ounces of luggage on my frequent travels
ps. hmmm... an idea for a thread? things you never ever needed yet wasted miletons (distance x weight) dragging with you everywhere...