The enlisted blues belt is white and should be able to be washed because it is cloth. You should be able to use a stain remover on it. Just let it hang to dry. If it doesn't work they are not expensive to replace.
I have never been able to clean that belt lol , I always just buy a new one. I can always get most the stain out , but if it's not perfectly white and clean my husband wont even think about wearing it!
Donate it and buy new, they are pretty cheap. We usually pick up a couple to have at the house just for that reason. He so rarley wears his whites but they have to perfect when he does
Re: uniform cleaning ?
What branch is he?
ETA: Nevermind, I see the pic. What material is that belt made from?