It is very simple -
Just delete the folder using appropriate activities -
Clearing cache basically means we have to remove a folder and cache will be cleared -
for firefox -
C:\Users%Userprofile%\AppData\Local\Mozilla\Firefox\Profiles\ .
for each cache2 folder in each profile folder in profiles
for chrome -
C:\Users%Userprofile%\AppData\Local\Google\Chrome\User Data\Default\Cache.
Mark it as a solution if it helps.