Kiln carving is a terrific technique that allows you to make custom designs out of fiber paper and impress them in the glass during fusing. The down side is you typically can use your fiber paper kiln carving pattern only once.
However, if you kiln wash the cut fiber paper pattern prior to fusing with it, it often will lift cleanly away from the glass and you can use it again.
Here are two little peace signs, the one on the left is kilnwashed, the one on the right isn’t:
After firing, you can see the kiln washed fiber paper easily and cleanly pops out, ready to be used again. The fiber paper does get progressively thinner and more fragile as you fire it again. It’s best if you can leave the pattern in place in the kiln and just add new glass to it. Although I have been able to use some patterns 3 or more times, I prefer to keep it at 2 firings because the details stay clear.