You don't have to be rooted to clear the individual caches of assorted apps. "Quick App Clean Cache" will do the job; paid app -- just under a buck. VERY eye-opening to see how much space some apps are truly using on a daily basis. I've been using it for several weeks and find it to be stable and smooth, operationally. Also super simple/intuitive to use.
Note: this app is essentially a front end, taking you quickly to the native settings area per app. In other words, that clear-cache function is built into the Droid, but it's a pain getting to it, per app, without this handy 3rd party app. No relation to developer. I just love his/her handiwork.