So what I do is load a 5 gal bucket with layers of trim and dry ice. Let it sit for like 5 min to really freeze. Put my bubble bag over the bucket and make it tight over the opening(mine are made for 5 gal) turn it over and shake while holding the bag to keep screen tight. I do this for like 30 seconds. Let it sit for another 5 min and shake again for a minute or two. I usually shake over a few pieces of parchment paper so it doesn’t stick and it keeps the table clean. It helps it you leave it a bit on the parchment paper to warm up and let the condensation from the cold come off it a little. Gather it up with a cleaned razor blade (they come packed with a coating of oil so clean carefully with soap) and keep in a bowl to dry more. Turn it over a bit after a day to make sure the moisture is gone. Do until it looks dry. I personally then squeeze into 1gm pucks using a pollen press but you can do so much with it.