I'm nervous about using ovens, heat guns, or torches to dry guns.
Things can happen, like an oven that's hotter then it appears, etc.
For that reason, I use a common hair dryer to warm guns and dry them.
This works well, fairly fast, and is safe to use.
You can also spray in a water displacement like WD-40, blow it out with compressed air then spray in a fine mist of lubricant.
To clean Cosmoline from wood, use cheap Walmart paint thinner on a rag or paper towel to wipe it down without getting it sopping wet.