I noticed the forums speak about adding in the polish, then running your system for like 30 minutes. Well here is how I do it (4 loads so far and ZERO issues with clumping).

Simply....

Pour in the amount of nufinish you want to
Stir with your fingers like your mixing cake batter. (heck for that matter grab your wifes mixer lol).
It takes me all of 2-3 minutes and it disperses amongst the walnut shells no problem.