I've been doing lots of research on leather crafts. They say that you need vegetable dyed leather in order to mould it. I don't know how my leather scraps were dyed but I'd be willing to bet that vegetables had nothing to do with it. Could I still mould it?
First of all I soaked my leather in boiling water because I wanted it to shrink and thicken. This particular scrap didn't shrink as much as others but it was good enough. I blotted it with a kitchen towel and then placed it on a paper towel on a cookie sheet and pinched slightly curved lines each a feather width apart. I kept going back to repinch the lines every half hour or so as the leather was so wet the lines kept softening. Supposedly there is an exact right time to mould leather after it has been soaked, but I'm too inexperienced to know when that is so I kept pinching for awhile.
Once I was satisfied that the lines were going to hold, I stuck the whole thing in a slightly warm oven for about 20 minutes. This isn't necessary and if you are the patient kind, you can just wait hours until it dries naturally.
Now go stick them in your hat (and call it whatever you want)!