I recently started using Grandpa Witmer's Old Fashioned Peanut Butter Mixer to mix peanut butter quickly and without a mess.
The kind of peanut butter I buy from Trader Joe's separates into two layers. The oil is on top, and the solid stuff is on the bottom. It's hard to mix with a knife or spoon. The oil is likely to spill on the counter or splash on my clothes. This hand-powered stirrer does a great job. I bought the model with a lid that fits my brand of peanut butter. The stirring rod slips through a rubber hole in the lid, and when I remove it, the rubber hole squeegees the peanut butter off so there's no mess. For me it was $12 well spent.
