Resin molds can be a difficult to clean, but there are a few ways to do it. The first way is to use a vacuum cleaner with the hose attachment. This will suck the resin out of the mold and make it easier to clean. Another way is to use a bucket and pour water onto the mold and then use a plunger to suction onto the top of the bucket and pull. This will cause the water to flow into and out of the mold, which will help remove any built-up resin. Finally, you can use a hairdryer on high heat until all of the resin has been burned off.