Cleaning the inside (footbed) of Birkenstocks? Any good ideas?

[pocketandsweet]

im a bit frustrated that mine look pretty much pristine from the top and the soles are still in good shape but a summer of lots of sand/dirt has meant that the bottom of my feet are stained by wearing them. Other than the obvious soap and water scrub any great ideas.

I've put every pair of birkis I've ever had through the washing machine and they come out fine. Use a 30 degree short cycle and chuck a bit more fabric conditiner in than usual.

I had a cheap high street knock off pair a few years ago and found making up a thin paste of bio washing powder, leaving to sit for a while followed by a quick scrub with an old toothbrush before rinsing made them as good as new.

Use an axe