i've heard if you melt the whole package in hot water, let all the stuff settle out of it, gently strain off the liquid on top with doesn't have hardly any DXM in it, and then eat/drink the stuff that settles to the bottom.
I am pretttttty sure this will work, because one time quite a while ago, I stupidly tried doing this, drank the liquid, and threw away the stuff the settled, and I didn't get high at all.
Sucrets always were my preferred way of obtaining DXM though. Seems to be the least foul tasting carrier of DXM that I can think of. Either way, now if I were to try it I would probably barf after a few of them, it's still gross as fuck to eat a whole box of sucrets.
I saw a video on youtube a while back where some guy did this with sucrets, then filtered it through paper towel, and then dried the result out, and had what looked like a reasonably clean DXM product.