how the hell do i use the outfit delivery stamps?

[Healfire]

When i go to mail i can't put the stamps in, they are grayed out :/

[Foxy]

I used them when they were first released so it's kind of fuzzy but I think you add the costume you want to mail and it adds in the stamps from your inventory automatically (i think).

[Healfire]

Ah thanks so much :) it worked