I thought that cooking off the bacteria was problematic. If not then I'm not opposed to cooking it. Time to pull out the Turkey fryer...
Why would it be problematic?
When you add plant roots, they are loaded with bacteria unless you dipped them in bleach etc and anyone using bacteria to mineralize would be adding non sterilize sediment anyway, so no need to do any of that in the first place.
You want to grow plants/roots etc, not bacteria really.
They will grow and cycle things later, so there's no real issue, roots will grow and so do the bacteria along with it.
I see no advantage for keeping the bacteria really and not just cook it, but spouses often will scream bloody murder if you used their pot, or oven. So that's a big trade off vs a muddy tray outside.
Bacteria will get back into the tank rather fast. Flush the tank 2-3x and then plant densely. This is what a number of folks in Brazil did about 10 years ago based on Vladamir's protocol:
"The use of earthworm castings requires some prep-work but offers excellent results: lush, healthy plant growth.
- A bucket for rinsing the castings
- Earthworm castings (without additives) - tap water
- a stove and pot for boiling the castings
Preparation: 1) Obtain 100% pure additive-free earthworm castings 2) Rinse the castings in your empty bucket - allow water to flow slowly thru. Turn the material over with your hand to distribute water throughout. Eliminate all that floats. 3) Boil the castings in a pot. There should be plenty of water so that the castings do not dry out. Boil 10-15 minutes, stirring occassionally. 4) Allow to cool. Deposit the castings back in your bucket, repeating step 2. Once again, eliminate all floating debris. 5) After thorough rinsing, the bucket water should become relatively clear. 6) Drain the bucket and place the castings in shallow pans or on sheets of cellophane in thin layers under the sun, allowing them to dry completely. The dried castings can be stored in ziplock bags for future use.
Usage: Earthworm castings should be used in moderation, and do not need to be completely dry for usage. They should be diluted with washed sand in a 50-50 ratio. The combination of earthworm castings and sand should approach 1kg of mixture for every 50 liters of aquarium water (for example, in an aquarium of 100 liters I recommend to use between 2 and 4 kg of earthworm castings). It is best to use the mixture as the first, bottom-most layer of your substrate. If you plan to build an extremely deep substrate, it can be used within the middle layers."