oxidation on lead pellets

Send them to recycling. Lead oxide is very difficult to remove and requires abrading it away (physically removing it) or using fairly harsh acids which will not do you any favors on delicate pellets. I imagine the time and cost to clean them properly would far outweigh the value of the pellets. So, the best option is disposal. Use desiccant packs and seal your pellet tins with tape if you need to store them long-term, and do not store them near corrosive liquids such as household cleaners.

shoot them, the coating will be removed as it goes down the barrel. and to prevent future issues shoot more often lol.

It's just tarnish, not one of the lead oxide compounds and is not abrasive.

I had some do that and sprayed a towel with ballistol and rolled them all around in the rag and then rolled them all around in a dry rag. Oxidation appeared to be gone and they shoot fine.

I had a couple of partial old tins in that condition. I gave them a treatment with that Wiscombe Honey Tom Gaylord talks about. The pellets looked better, I used them and my guns didn't seem to suffer any damage that I could see. Mind you all of my guns are 12 fpe or less... not sure if it would be an issue at higher velocities.

Lead oxide with not hurt your barrel. You can shoot them. I also used Ballistol on a rag couple of times some on a rag then drying them with another rag. I just went and looked at them they appear to be very good. If there's still oxidation, you can't see it. They where done several months ago.