Is it OK to give pine cones to gerbils, both for the seeds and generally as something to play with and gnaw?

Yes I would suggest clean them and freeze them though before giving them that should kill all the things that could harm them.

I was thinking of baking them in the oven to kill off any nasties.

And I was wondering if anyone already feeds them to gerbils and it is OK, or if anyone knew of any possible problems. It seems an obvious natural food. The seeds are likely to be full of nutrients, gerbil food usually has various seeds in it. The cone itself should provide plenty of interest and gnawing opportunity.

Not sure about baking them they may break differently after baking like bones become dangerous for dogs.

I'd not considered if that could happen. It seemed to me that plenty of bacteria can survive freezing, so I thought baking would be safer.

I think freezing them kills most things. Cones are only safe bit of the pine to give entire rest of the tree contains a poison which can kill !

Yes you can give them pine cones, most love them!. You can freeze or bake them to kill off any nasties, freezing is considered better though only because they smell when baked. Pinecones are safe because there's no sap in them as their not part of the tree trunk or anything that produces sap, however bits can get stuck on cones, so make sure you scrape it off as best as possible. The seeds are fine.