I recently wondered if I could compost peanut butter. I would assume it is fine since it is an organic material. If you can compost it, what are the pros and cons to doing so? Is there anything else I should know about adding peanut butter to my compost?
This question covers similar ground. See especially @baka's comment there:
the fats and oils slow down "bug" growth
If you are composting a little bit of peanut butter then it should be ok -- e.g peanut butter on a bagel that didn't get eaten and ends up in the compost bin.
But I wouldn't dump a whole jar of peanut butter into the compost. The issue is that peanut butter is mostly fat. Fat doesn't compost well. It will take longer to break down and will end up as a gooey, smelly mess in the meantime. It may also attract unwanted pests (raccoons, rats, neighborhood dogs, etc.).