I wouldn't want to try because of some the materials that cycling shoes are made of.

Actually I've never thrown shoes into a washing machine in my life. And I probably never will unless it's a cloth slipper, a simple constructed thing.

When I saw it being done by others, I thought it looked abit gross.

But then I come from a family that took off any shoes that we walked around outdoors before we entered in a house. Either slippers, socked feet or bare feet. To this day, those are my habits.