Dude, do NOT heat your K. Trust me, I'm the k king. I spent 2 years driving to mexico every other weekend to buy vials.
You only want to "cook" 1-2 vials at a time. Get a big pyrex dish, like a casserole dish. Rounded edges are better. Poor the K in. Get a blow dryer set on low and move the pool of liquid around the pan w/ the blow dryer. Like your painting the pan, just keep pushing the pool of k all around the pan. Blowing it back and forth up and down, all around the pan.
Soon as enough of the liquid leaves there will be a film on the surface of the "pool". This is when it gets even more important to move the pool around the pan. Soon the solids will start to stick to the pan, when that happens push the liquid off the solids. Soon you'll be pushing sludge around the pan and a clearish film will start to form all over the pan. This film will go opaque as it drys, keep blowing w/ the hair dryer til it's almost all opaque.
A note here- if u did not move the liquid around enough some liquid may be trapped between the surface film and the film that deposited on the pan. You can tell because it won't dry and there be like a cracked surface film of big flat chunks of k sliding around. If that happens just spread all of the stuff around w/ the tip of your index finger to break up the solid surface film that's trapping the liquid underneath. Then blow dry low til everything is white. Take a razor blade and scrape all that film off the pan, forming a pile of powder in the middle. That's why u want rounded edges, so nothing gets trapped in any corners.
If you heat ur k your losing potency- no matter what. My k vendor in mexico taught me this method. The more pink your k is after cooking the more you've killed w/ heat. Just be patient, this method works.
Also I get k in sealed vials so I know it's safe but I still don't IM. Absorption is too slow, hard to hit a hole that way. Snorting it sucks, but it works best. I only IM when my sinuses swell shut after doing 2 grams in 4 hours.