Don't put edible things in film canisters, apparently they leach nasty plasticcy things into all that they touch. What they are great for is as a duck tape carriers. Simply wind it around the cannister and hey, no more great big roll of tape cluttering up your pack. Cunning huh?
Zip ties, aka cable ties are those plastic / nylon fasteners used to tied bundles of cables together in cars etc. You can get re-useable ones, but most are not, you have to cut them off.
Other top tips, er, cereal sacks are great for travelling in South America. Big, old bags - put your rucksack in one and it'll protect it from the dirt and grime in bus luggage compartments and also look like a cheapo, local bag rather than a valuable gringo thing that might be worth stealing.
Elasticated bandages - stick one on your bicep, under your shirt and conceal some cash in it. Ankle wallets - same principle, all competent thieves know that travellers wear those daft waist belts.
Why a half-eaten container Sofa Man, surely an intact one would be more useful?