I really try to avoid using a lot of chemicals and none are needed if you heat sterilize. I used to boil the leca and then tried baking/broiling it, but honestly they both stunk up the house so much...and I got tired of hearing the Hubby complain about it. I wound up putting it off until he was out of the house and it was a real pain.
So, now I BBQ it! Yes, it sounds funny but works great. I've got a pretty fancy grill with thermometer and I put the leca in old pie plates etc. and BBQ at 500 degrees for about an hour. That's probably overkill for virus etc. but I like the particulate matter to turn to dust as it much easier to wash out later. I then put the BBQ'ed leca in a colander and rinse all the junk away. Rinse, rinse, rinse until there's no more dust or anything catching in the colandar holes. Then it goes in the sterilized bucket for future usage. The good thing is no odors inside and no mess to clean up.