The resin seeps out from the raw material of the pine coaster, making it impossible to clean and polish

I have brought a few of the TEMU coaster blanks.. Both the rounds and the squares. I am having some problems when I do fills in that the edge tends to bleed resin, which makes cleanup and sanding almost impossible.
These are raw pine wood.
Does anyone have any suggestions?? Does the wood need drying,treatment etc.