If you are new to kilnforming, I strongly encourage you to subscribe to Bullseye's instructional videos. You get access to about 100 videos for $45 per year, and if it saves even one project, you will have saved that value and more. https://videos.bullseyeglass.com/videos ... trailer-2/
Here is a link to our video on preparing kiln shelves https://videos.bullseyeglass.com/videos ... n-shelves/
This particular video is free, so enjoy!
You do want to dry your kiln shelves in a warm place (like a kiln) to drive out any humidity that could provoke bubble trapping during the glass firing. This might not be necessary if you are in a very warm, dry climate.