YI can’t get washed and sterile silicone stoppers. As mentioned before, I only use silicone. So I just wash them in mild, soapy water, rinses like crazy, wash with iso alcohol and then distilled water. I use a salad spinner between each step to remove gross liquids. Then I put then in my lab oven at about 200c for probably 30 minutes minimum. I say probably because I put them and other things in the oven and then do other things in the lab. Some of my vials are in there for hours.
Unless you have an accurate oven I think 150c would suffice. It dries them out and “sterilizes” them.
Before I used this process I placed washed stoppers in a jar of BA and pulled them out one by one when capping.

All of this is time consuming. No getting away from it.

THX, congrats on ordering a hood. Let me know if you need any help with it. They are pretty straight forward though. Hope you ordered a horizontal one.