I'd advise against putting your shoes in the washing machine, not least because all the detritus will ultimately do for the machine also. Undo the laces right down to the bottom, remove insoles, wash in plain water (without soap) using a decent brush. Pack with newspaper and leave to dry somewhere where the air circulates and never near or on a radiator. Shoes are the one bit of a kit that are really important in running so you should look after them big style - and then they will look after you. Never pull your shoes off without undoing the laces completely, this only stretches the tops and will (on the fell at least) lead to poorly fitting shoes, blisters and even the loss of a shoe in boggy situations. Ideally buy multiple pairs (2 or 3) and circulate them. This allows them to dry properly and enables the midsole to recover. Using your shoes on consecutive days will only lead to faster degradation of the cushioning, so the economically-minded will be quids in if they buy a few at a time and use them as suggested. I could go on, and on, but you probably don't want to hear it.
Yours sincerely,
Imelda Marcos