Never use thermal receipts for girricks / filters or any other general printed media. They may contain BPA and a number of other toxic chemicals. Sometimes I make a girrick from rolling paper but they are very fragile but are smoke able if you are into roaches. If you are unsure of the paper you can test if its thermal by applying little bit of heat from a lighter. If it turn dark with a poof of smoke it gonna be death to your lungs and fertility. Keep it safe.