Ok. Preheat oven to 215F. Spread out you trimmings on a cookie sheet. Place in oven for 30-40 minutes.
Put 1lb butter and 1 cup water in a pot on stove. Melt but DONT COOK. Once the trim is done, add to pot. Keep on LOW for 3 to 4 hrs.
Use cheesecloth to strain it into a container. Let it settle. I usually stick a straw or something to the bottom. That way once it hardens, the water left over at the bottom can be easily drained off.
To refine it further, I place the container in warm water until melted. Then repeat process of cooling/straw/pouring off junk.
And no, you dont need to use butter. You will need to use something to strip the trim of its oils/thc. Like alcohol. Then use that mixture to make oil.
I make infused coconut oil. Quick and dirty, I shred everything in a food processor and throw it on low in a slow cooker with enough coconut oil to cover it by a half inch or so. There are more refined methods that involve a water bath at 108f for days I am going to try next. Enjoy your harvest!