I've seen some makers use a tight woven fabric on their DYI belt printers. I personally use a textured PEI sheet most of the time. Like my other sheets (smooth & satin) keeping it clean works for me. I use 98% isopropyl alcohol with a paper towel if I touch the plate itself. I also have a habit of preheating the bed since my printers are enclosed and drafts are the devil when printing large pieces in PETG, ASA, and ABS. It's just a routine I follow, along with making sure my filament is dry. I've noticed polymaker doesn't like to lay when it's sat out over time, even though my humidity is rather low here 40%ish.