Moving backward, you put way too much butane through it. One to two cans would have done it. Check the color of the butane coming out of the column to see when it is time to stop.

Moving forward, if I was looking for something to vaporize, I would place it in a shallow container over low heat ~160F, and let it sit and out gas for awhile longer.

If I wanted to ingest it, I would stick it in a 240/250F hot oil bath and cook it until it was relatively bubble free.