Dear hunters,

I need some imformation on slate calls. The crystal calls need to be roughed up with sandpaper before use, Does anyone know if the slate calls need to be roughed up before use? Slate is very inexpensive at our local aquarium store. 2.00 a pound..I believe I could build my own. I saw some pictures of them on ebay and one of them appeared to have come with a piece of abrasive cloth.
Thanks,
Chuck