Jirohnagi
Braava Braava
It is kinda hard to clean, but we have been using towel and cleaning spray meant for dog wounds that we got from the vet, sometimes moisturized piece of tissue ( I really don't know how to describe it), also I don't often watch the process, since it disgusting. It often creates big scrap when it has been emptied, so it's kinda safe from bacteria and stuff.
And we know it's propably not caused by food, since it appeared after we got him his vaccines adn the vet who gave the vaccine shot it in the wrong spot, causing the interstitial fluids to gather to same spot and rasie his skin, creating the abscess. Although our dog is really picky about his current food, he often (which I mean always) push most of the food over the bowl border and he eats only certain kind from dog cereals.
Cleaning spray sounds like it's Saline solution with a bit of iodine in it (closest i can think of) this is good. Now the ahh somewhat gross question are you letting the dog get at it as in lick it? Also do you keep the wounded area open or covered?