Been trying to solve this one for a long time... , cleaning caches and logs releases a couple of Mb, but if your phone's internal storage is small (i.e. Samsung Galaxy Ace)  no matter what you do -  the phone will fill up again in no time. I have no such problems on my Desire HD, but my wife has on her Galaxy Ace which has very little internal storage.

    Well, there IS a solution. Here's what to do:

    * root your phone (It is rather easy to root some phones, i.e. Galaxy Ace in question - just copy the "root.zip" to your SD card, boot in system recovery and update from "update.zip")

    * then install program called "Link2SD". No, this is NOT the same as all other apps that move programs to SD card. Link: https://play.google.com/store/apps/details?id=com.buak.Link2SD&hl=en



    * Now, you have to reformat your SD card. The instructions are given in description of L2SD, but let's repeat here:

        ** get program Minitool and install
        ** backup your SD card to computer
        ** run Minitool and make 2 partitions - both should be primary
        ** first FAT partition is your standard SD card storage
        ** The second partition is used for application files and can be ext2, ext3, ext4 or FAT32.. Should be smaller, i.e. 512Mb-1Gb should probably be enough.
        ** Some phones don't support ext2, ext3 or ext4 file system and you may get mount errors like "no such device", "invalid argument". These phones have to use FAT32. Funny, I did this twice on exactly the same phones (Galaxy Ace) and once it worked with ext3 second time it didn't and I had to use FAT32. Probably because of different version of software (firmware), so it might be a good idea to install latest firmware.

    * Link2SD mounts the second partition of your SD card and makes OS mounts it at boot time

    Then you can move your apps to this 2nd partition. You have been able to achieve similar thing by moving apps to SD card from android, but not all apps, i.e. some just didn't support this, and all apps with widgets didn't work. With this method, all apps work.


    Don't worry connecting the phone to PC or dismounting SD card. All your apps on SD card will still work because they're on other partition which won't get dismounted! With regular App2SD apps, this would cause problems because apps were on SD card, on the same partition that gets dismounted, but with this method, the other partition remains connected

    But more important, you can also move updated apps from internal memory to the system, so they don't have to be on your phone twice. Just click and hold the app you want to update and select "Integrate app into the system" option from the menu.

    I.e.: you phone comes with Google Maps, GMail, Play and several other apps. I mention these 3 because they occupy pretty much space. These apps are in system partition. When you update these apps, the original remains on your system and the app is installed again on your internal memory, thus occupying more space because it is there twice! With Link2SD you can replace apps in your system with the updated ones, thus saving a lot of internal storage!

    I managed to free a total of 70Mb on my wife's Ace with this by moving ALL apps to SD card and moving updated apps to the system.... OK, when the cache filled again, it took like 20-25 Mb, so now there are like 40-50Mb free, but remember - I created 1Gb partition on SD so there's a lot of space for any new apps there!!! You wouldn't have to use the internal memory for apps anymore