So this isn't really a home-improvement question but I think the people here have the skills to answer it. If there's a different site you'd recommend asking, please let me know and I'd be happy to move it there.
My wife and I got a salad bowl that was hand-made by my uncle as a wedding present. It has sides that are perpendicular to the bottom of the bowl. At some point a pot lid was placed on the bottom. Nobody noticed that it fit around the bottom of the bowl well. In fact, it fit a little too well. We just noticed that the lid is firmly stuck to the bowl.
Becuase it was a hand-made family wedding gift, I want to minimize any possible damage to the wood bowl. But the solutions I can think of to separate them are contradictory. Our apartment has gone from the usual summer 75 F to a comfortable fall 70F. We don't have a thermostat or control over our heater (this is normal in our city). So I assume the metal getting colder and contracting doesn't help things. But it also means it's less humid so the wood should be swelling less. I could put it in the driest location I can think of, but that would be even colder, causing the pot lid to contract more. I could apply heat to the lid, but most ways I have access to involve steam or hot water, which would swell up the wood. Then there's trying to add oil or soap to the place where it meets, and even if I could get those between, the slipperiness interferes with anyone trying to grip them and pull them apart.
What would you suggest for getting this metal lid unstuck from around the outside of a wooden bowl?