Quick notes before you start:
Clearing caches can sign you out of websites and may make apps slower the first time they relaunch.
Don’t delete folders called Caches themselves — only their contents.
If you’re not comfortable, make a Time Machine backup first.
Open Finder.
From the top menu choose Go → Go to Folder…
Type ~/Library/Caches and press Enter.
Select everything inside (⌘A), then Move to Trash.
Again Go → Go to Folder…, type /Library/Caches (this is system level) and press Enter.
Select contents and Move to Trash (you may be asked for an admin password).
Empty the Trash and Restart the Mac.