İ dont have that option to click. Maybe should i update my blender? İm still on 2.8
Try that down line arrow on the right edge of your screenshot.
Uhmm. İ dont have “remove unused slots” . I only have copy material ,paste material and something other.
Judging by your screenshot, there are objects that still are using the materials you want to get rid of, otherwise those slots would start with a zero (0_UWRPD.027 for example). You’re gonna have to change the object using that unwanted material to a material you want to keep. Save your file and reopen and they will have evaporated away, leaving your file spring-breeze fresh and clean.
I’ll send you my bill.
You are right . . . your version of Blender does not include this option … (Version 2.80 rc3 july 2019)
In version 2.82 it’s OK