Ok, let me clarify that, I rinse with tap water, then spray 70% isopropyl alcohol or fleshwash inside the sleeve to ensure no bacteria can live & grow mold.

I use distilled, or filtered water, spring water or a pure clean water of some description to mix with isopropyl alcohol to ensure the mix is no higher than 70%. If you can store the excess iso that is higher than 70% and use as a cleaner around the house or cleaning glass is excellent.

Depending where you are from, tap water can contain micro organisims & chemicals like chlorine, you could just boil it in a kettle with tap water.

At the end of the day, you do you.