Could it be that Wick it uses a different coating on their sample wicks than wicks unlimited? I'm not really sure, just guessing. I've never used Wicks Unlimited but I do use Wick It, and I know when you order from them they give you 4 coating choices for your wicks... Standard Paraffin, High Melt Paraffin, Natural Wax, and High Melt Natural Wax.