the method you are doing is the silk screen then the hash gets wrapped in plastic and wet paper and put in the oven .this is the same method i use and if you put it in the microwave then the heat would be to much and destroy the hash otr as del says lower the potency some what.The reason it is wrapped in wet paper is so that direct heat is not on the hash but the wet paperso just stick to the wet paper method or make bubble hash hope this helps .the posman