Canndo. Can i case with compressed coir. Idoń have notjing else to use. I have some soil that mixed? I was thinking maybe microwave it for 5 minutes to kill everything so theres no nutrients
No.
Coir is very nutritious for the myc and tends to lead to overlay.
Microwave will do nothing in this case.
The basic physical structure is the nutrient.
Also, you don't want it sterile, you want is pasturised.
Sterile is for BRF and grain jars.
Use it with verm and gypsum for substrate, sure, but case with peat/verm and a bit of lime for ph.