In reaction to the canister, on my oldest sons birthdayparty we were stuck inside due to the rain.
Since my Speedlite 160E (look it up, it's like 20 years old, lol) doesn't have a diffuser available I went looking for a canister since I saw it on DIY-Photograpy once.
Couldn't find one (all black here) and eventually found myself in the attic near the washing machine.
We use these little transparant bowls that look like this for detergent:
So I took one, cut out some space at the edges and put it on the flash.
It worked fine.
I can't use it outside or in crowded places, tho.
It comes off easiliy, so I have to stay careful.