hi is there any app/script to clean the system after uninstallation or just to clean up old temp files etc?

When well written, debian package files will uninstall cleanly, leaving behind only their configuration file (this is a feature not a bug). If you want to get rid of them, too, consider apt-get purge - but before you better are proficient on the command line.
I don't think you'll need to erase the config files, though, which are tipically small text files which won't clutter your disk space.

Blame the apps not doing this instead.
No need to invent just another tool for working around something...