Specifically, 1) should I remove the PPAs from apt first, then purge the packages I installed from the PPAs, or vice versa? [20:08] !ppa-purge To disable a PPA from your sources and revert your packages back to default Ubuntu packages, install ppa-purge and use the command: « sudo ppa-purge ppa:/ » – For more information, see http://www.webupd8.org/2009/12/remove-ppa-repositories-via-command.html