Here is a tutorial on what files/folders you can safely delete/clear in your Sims 3 folder
First go to the start button on your pc
You should be seeing something this, click on Documents ( depending on what windows you use or if you are on a MAC use your usual way to open Documents)
Once you have Documents open look for Electronic Arts – click on it then click on OPEN
Still with me? Great. Now that you have EA open you should see The Sims 3 folder. Click on it and then click on OPEN
Now you should be seeing all kinds of files. You have arrived at your final destination. Here is where you will find the cache files you will want to delete. Scroll all the way down to the bottom of the page till you see these
click on each one of these: CASPartCache, compositorCache, scriptCache, simCompositorCache and socialCache, right click on mouse select DELETE. Do this after installing/uninstalling patches, CC, store items, and after long periods of game play.
Not done yet! There are still a few more you can clean out. Scroll all the way back up to the top. Now look for DCbackup. Click on it and click OPEN. Once inside highlight (hold left side of mouse down and drag across all files EXCEPT CCMERGE!) Click on DELETE. If you have a lot in this file you may have to highlight and delete in sections. Do the same with WorldCaches. Click on it, open it, highlight everything in there click DELETE.
One more file you may want to check. In the DCCache, click on it and click OPEN. If you see anything with .ent after it, DELETE IT! You can also delete the .missingdeps.idx file.
Another thing I do to help free up space is take all your screenshots out. I have a separate folder in my documents for in game screenshots. Do this also for any video’s you may have done while in game. If you have a lot of Exports but don’t want to get rid of them, you can either save them on you computer or a thumbdrive.
Hope you have found this tutorial on cleaning out your game helpful.