Have you tried Vanish Oxi stain remover?

I use vanish on a cloth with warm water.

I always put my white caps in the dishwasher.

Deno

Deno, not heard of that one, doesn't it the cardboard in the peak?

Did you try it?

What were results?

Martin
There is a plastic hat form which holds the shape on the entire hat in the wash.

Deno

Martin
The "peak" cardboard to me would be in the top of the hat which is tucked in the hatband, is removable. I think the plastic form should do the trick. I just toss mine in the dishwasher since I prefer a slightly bent "bill" on my hats.

Deno