I am planning on using a 50/50 mix of worm castings and straw as the substrate in my next grow. I have read that pasteurizing castings via hot water pasteurization in a pillow case can get messy; namely the castings turn to mud and leach out of the pillow case. I have no access to an oven in my current residence, so I cannot pasteurize the castings there. However, I do have a 5 gallon pot that can hold 6-1qt jars, and a small alcohol stove capable of bringing several gallons of water to a boil.
I was thinking of using the following setup to pasteurize my substrate mix without allowing the castings to leach.

I plan to:
-soak the the straw for several hours
-add lime to boost pH
-then mix straw, castings and water, bring to a little wetter than field capacity
-pack into jars
-Heat until core temperature in center jar is 160-180*F, hold there for 90min.
-Allow to cool
-Check Hydration
-Mix with grain spawn.
Should this setup be effective in pasteurizing the castings/straw mix without allowing the castings to leach? Should I simply leave the lids on the jars loose, or just take off the lids and tin foil them? Will the jars burst? Any tips, ideas, or suggestions are welcome. Thanks