How to Uninstall .pets in 4.2.1

[davec51]

Like others I have had trouble uninstalling pets that I have added to 4.2.1, resulting in a frustrating and usually incomplete manual uninstall.
However, I stumbled upon the solution: If you installed the program from the pet3 repository, switch to that before you click on the installed program (below the repository). Then it will uninstall.
Like most people, I loaded the pet-get program, which defaults to the pet4 repository, and tried to uninstall from there.