First there is a small problem with the product description. I applied this product to a black baseball hat. The product smells like shoe polish when first applied. So its not odorless and you can use it anywhere.

It goes on like a waxy paste, sitting up on top of the fabric. You heat it with a hair dryer and it melts into the fabric. I waited overnight for it to cure.  (Note. when it first goes on it is the constancy of shoe polish --paste. It does not disappear. The cloth is coated and greasy. You have to heat it. Don't overdue it on the brim of the hat since its hard to make it disappear on harder surfaces.)

I'm glad I experimented on a hat I didn't wear first. Once on and cured --it does water proof very well. 3 days later and the smell is practically gone.