Some background. Whilst car camping down in Weymouth recently I was unfortunate enough to encounter a stomach bug (we initially thought it was food poisoning but later realised it was a bug as my other half developed the same symptoms over 3 days later). I ended up making a mess inside the tent, though not as bad as it could have been (this one was mostly just water).
My sleeping bag became unusable however, and this was on the first night, so I slept under a blanket instead, as luckily the weather was still surprisingly warm for September. My other half kindly cleaned up as best he could - the tent seemed to wipe clean ok and was done immediately - but my pack and my sleeping bag took the brunt of the mess.
Since we were only there for two nights we just chucked most things effected into the back of the car, but obviously if we had been trekking instead of car camping this would not be possible.
My sleeping bag is synthetic and machine washable (as stated by the manufacturer on low heat, no or low spin and only a tiny bit of detergent, no fabric softeners) and now lovely and clean. Again, this isn't exactly something I can manage out on a trek in the future - plus we had plenty of towels with us due to swimming etc, which we probably would not have with us trekking. Also as vomit is a rather nasty thing to clean up anyway, I'm not worried if things get dirty but obviously vomit is completely unhygienic, so I would assume it need something more thorough than a splash in a stream like you do with grubby boots.
So my question is: When out trekking, what is the best way to clean camping gear of vomit?