Safe to delete Google's Update folder?
Solution 1:
It is safe to delete all old Chrome versions from that hierarchy, though it is policy to keep the last two.
Chrome ought to do this itself, but fails on occasions.
You do not need to clear any other browser caching (unfortunately, the first answer posted seems to have persuaded you to do that, unnecessarily :(
Path to backup versions isC:\Users\Username\AppData\Local\Google\Chrome\Application
or to type in Start without fiddling with hidden folders…%localappdata%\Google\Chrome\Application