Doing it safely can be tricky – fortunately Ubuntu Tweak can do this for us.
Remove Unwanted Packages
There are a few issues involved in removing a PPA.
The simplest is to remove any packages that were provided solely by that PPA.
The exact command will depend on the packages you’re gonna wanna remove.
The first step is to install Ubuntu Tweak if you don’t already have it installed.
Open Ubuntu Tweak, and select Package Cleaner in the list on the left.
press the Purge PPAs button near the right.
If the list of PPAs is greyed out, hit the Unlock button and type your administrator password.
choose the PPAs you want to remove by clicking on the checkbox next to them.
poke the Cleanup button when you’re done.
You’ll be prompted to downgrade packages that have earlier versions in the Ubuntu repositories.
In our case, we are removing the PPA that contains nightly builds of Mozilla Firefox.
Click Yes and Ubuntu Tweak will do the downgrade for you.
However, we recommend keeping Ubuntu Tweak around for all the other neat things it does!
