* For more detail on .vpk file , please refer to my guide:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2848732323
.
https://steamuserimages-a.akamaihd.net/ugc/1760364156127169325/A8C5001BA567F89280B7C9D72D87EF712A7915AA/
A weapon mod will look like this . First thing first , make sure the skin you want is for the right model ( example , skin for MP5 from MW2019 can't work with MP5 from CSGO ) . Then you download that mod , extract it and you will get those file like in pic above .
Now only keep "materials" , delete everything else . Repack into .vpk , rename it to something easy to find , and put it into "addons" folder .
To remove the skin , remove that .vpk you just repacked .