I use a beater from an old hand mixer inserted into my M18 drill. Just have to be careful near the top the jar to avoid peanut butter spray on the counter. And

I use a beater from an old hand mixer inserted into my M18 drill. Just have to be careful near the top the jar to avoid peanut butter spray on the counter. And my shirt. Edit: works best if the jar is stored upside down for 1-2 days.