What to do about stinky feet?

my husband works outside, it's cold, so he's got heavy boots that keep his feet warm. . .but his feet stink like death after a days work . . . we've tried goldbond powder, but is there something we can do? i mean yes, duh, he showers and whatnot, but it's soo bad when he takes his boots off after work. no smart alec answers please. .