Thank you for the response. I'm hesitant to try as I don't want to ruin the inlay with the heat. If I did do it, it would be tacked down with small brads, so hopefully it will stay still. When I heated the horn to flatten it I did it a low heat for like 20 minutes. How hot do I have to get the ferric nitrate to react? Just planned on using a normal heat gun. Hoped the heat wouldn't bother the inlay as I thought the heating process was at a higher heat, but s shorter time.
I'm stuck in socialist NY as well. I feel your pain.