I've got a big bag of Sichuan pepper but I've often found that when I cook with them it's difficult to avoid grittiness from the outer kernel. I don't have this problem when I visit Sichuan Chinese restaurants and the pepper was bought from a big Asian supermarket.
What do I need to do to prepare them to avoid the grittiness? Is it really as fiddly as picking out the peppercorn from each kernel or is there something simpler that I need to do?