Ditto on the make sure its oil free chalk. I only chalk my lid, it will transfer to the sound boards. Myself I dont sand anything unless there is a slick spot that can not be roughed out with a 3m green pad. I use a green pad on the sound boards to clean them up before a hunt, to ensure no finger grease is on them, and look for finger spots on the lid incase my kids snuck a spot on them, if so I green pad it before chalking it. Shallow Rio may have more advice for you, than me. He taught me what I know....Jim