The useless lump of lard known as my lad (!) has somehow managed to make his "skateboard" boots (cost c. £60+ - a present from the grandparents) smell so foul you can smell it from the next room.
No idea what he's done ... although it seemed to start when the snow was bad. Presumably he left them damp, kept on wearing them[1] etc etc.
Short of throwing them out, is my instinct to put them on a no-spin wash in the washing machine sensible. Obviously they'd have to drip dry and then dry out 100%.
They're some sort of synthetic leathery material, with a fabric inside.
[1]*You* try telling him. 16 years old, and knows everything there is to know. Actually it was unfair to call him lardish - he's painfully skinny if anything (not sure where that came from ;) )