I've found that, as I invariably forget to take a towel with me, if I'm really muddy I will probably also have soggy wet socks and these make excellent flannels for a quick scrub of my legs before getting in the car. The added bits of heather and stuff that are often stuck in them are good for exfoliating too

Sounds disgusting but it works. Also, on the rare occasions that I moisturise my legs before a run, that definitely seems to help the mud slide off afterwards. Boots Botanics body lotion in case you are wondering.
