I can't afford to buy sterile compost to use when potting on plants so, I microwave my own. First I sieve it to get any large creatures out (microwaved worm is not a pretty sight) then put in a 2 litre plastic pot and microwave full power for 7 minutes. So far (three years) no explosions. The compost needs to be slightly moist to start with. You need to let it cool down before using it. The smell needs to be experienced to be appreciated. It seems to kill bugs/weed seeds/fungus. Large scale sterilisers are out of my league.