I used muslin hop sacks the first couple years. They do make for easier cleaning/pouring chilled wort into the frmenter. but I got a large dual layer,fine mesh strainer form Midwest (NB has the same on),so now I just dump the pellets in the boil. I think adding pellet hops loose in the boil gives them a bit more edge. But whole leaf hops will still go in a muslin grain bag. Too much bulky mess for the strainer.