If it’s not crashed and no visible crystals then heating it isn’t going to sterilize it or make a bit of difference. Is it in a vial with air sealed topper? If so, then use it. Gear is usually G2G long after the expiration date. You can always send it to me and I’ll let you know if it’s ok, if it isn’t up to snuff I’ll properly dispose of it for you...

If you’re hell bent on heating it up, don’t go over 200 degrees or so and leave it for 3 minutes or so. I don’t know your oven, but guessing around a 2 or 3 on the dial. Can use a thermometer if you’re feeling crazy.

In all seriousness though, you’re overthinking it. No crystals, no problem