It is a matter of getting used to sluicing oneself off with whatever water one can find (taps, hoses, rivers, even rolling in the wet grass, or walking through reeds and the like works), and avoiding fabrics that hold onto the mud. Go for waxed cotton, oilskin, nylon overclothes. And, unless you can see a viable method of removing it close at hand, try not to go in the mud in the first place
When young I was called the mud magnet. I used to love puddling about in mud and have been known to come home with wellies full of the stuff much to my parents horror and exasperation.
I can't bear getting muddy now but somehow I still do.... perhaps it's something to do with living in the countryside.... Or am I still a mud magnet?
I usually have a few rules that I like to follow when camping in wet/muddy conditions:
1 - Spread leaf litter/mulch around areas that become extra sloppy - this is usually a problem when camping in a group as you're all trampling around in a concentrated area. The debris helps to soak up some of the sloppiness!
2 - Be more selective of camping spot. I avoid chestnut woodlands in Autumn/Winter because the saponins realeased by the chestnuts take the mud to another level of muddiness. I find that coniferous woods can be a bit better as the pine needles give you a bit more of a barrier from the mud.
3 - Keep your kit tidy and squared away. Good camp drills!
If it rains here, it will be muddy. I just rinse off in a stream or ocean, if it isn't dangerous to do so at the time. Or even in the rain.
I do not want my feet to stay soaked, so I pack sandals. If I am on a trail in sandals, I might pack shoes. I like light, so use trail runners. And I pack a gamcha (a thin cotton towel) that I can dry off with and even wear while my clothes dry. The gamcha is so thin that it will air-dry very quickly.
I don't really mind being muddy, so long as I can clean up easily.
I was emptying one of the huge dalek type compost bins a couple of weeks ago, and Himself came out to see what I was up to.
"Oh look, she's muddy, she's happy", said he with a smirk He's known me nearly fifty years, he's gotten used to it.
Well I was I was busy, I was outside, I was doing good work, and the mud was just par for the course. The soil from the compost bins was beautiful stuff though, just as well since we're on heavy clay soil here, and if I don't keep it full or organic stuff it sets like bricks with pottery slip on top.
Getting your hands (Hah! and everything else) mucky isn't a crime, it's a good thing. Does your immune system good to get dirty.