I had great luck killing spidermites off (knock on wood) with 1 part 90%iso alcohol and 4 parts water and enough dishsoap to throughly coat the leaves when sprayed
First day i sprayed a 50/50 water/iso with soap.
(This will fry a few leaves so definitely do in the dark )
Then follow up every day with 1/4 iso/water
For 5 days
Easiest method i ever used for.mites
And the plants bounced back in about a week.
Very important you do it for at least 5 days
So you can catch all the hatch cycles
It worked for me . Last time o ised harsh chems and they still came back. This time nothing
Also when you first spray your plants clean first and vacuum all the cracks where they hide then
Spary your room in alcohol as well as the plants .
Use. Resperator if you have one . Not so much toxic as just haarsh And dont lite a cigarette in there please
Edit to add if its spider mites