smearing is good. sparks won't work if the cotton wool is overly soaked with vaseline. lots of guys will stuff a 35mm film canister full of vaseline smeared cotton wool balls. eventually the vaseline seems to even out.
i got a load of tiny zip lock bags from a rock'n'gem show. i can make great little individual packets. it seems that the vaseline degrades the bags after longterm storage, or perhaps it's just hard to open a vaseline covered bag. but they often rip. so i just cut the bag and burn the lot, works a treat.
cheers,and.