What's the most effective way to mix a jar of natural peanut butter? When you buy a jar of natural peanut butter, it typically has a layer of oil on top, which has separated:



Mixing it can be messy and time consuming.

Aside from slowly and patiently mixing it with a knife, are there any tips and tricks to make this job faster, and  without spilling?
I've done this with almond butter, and I imagine it would work for peanut butter as well. The secret is to buy it a month or so before you need it, and then store it upside down for a week, so the oil traverses all the way through the jar and its contents, then turn it right way up for another week, and repeat again in each direction. Each trip through the jar mixes the oil with the solids a little more, and it's fairly homogeneous after four turns.