Can't remove printers - Ubuntu 16.04

[rikona]

When I finally got the UEFI problem straightened out, the installer on
the new Ubuntu box did a good job of tracking down printers on our
local net, but it did so by using all of them shared by the old Ubuntu
box. They all came up working fine. 

The problem is that the new box is going to replace the old box, and
so I had to install the printers on the new box. That went well - they
all worked on the new box as direct connections for those printers.
Since the old box was going to be removed, I tried to delete the
printers that were tied to the old box. The "printers" GUI has an
option to delete printers, but it didn't work for any of them. It
looked like they were deleted, there were no error messages, but the
icon and the printer were still there. I then tried accessing CUPS via
localnet/multiple browsers, which also gave an option to delete each
printer using CUPS, but that didn't work either. I tried using sudo
[some browser] using CUPS, but that also didn't work. I tried using
sudo lpadmin - that did not give an error message, but also didn't
seem to delete the printers. Although, after using lpadmin, I did get
two error messages in the "printers" GUI when I tried to access the
properties:

Option 'orientation-requested' has value '0' and cannot be edited.

and

Option 'print-quality' has value '0' and cannot be edited.

But, even with these error messages the printers were still there.
Also, it seems that these printers are set up as "classes". In the
CUPS/browser interface is also an option to delete printers from
classes, as there is in lpadmin as well, but I could not delete these
either, even using sudo access.

So, at this point I'd like to learn how I can actually delete these
printers that will not be there when the old box is removed.

Thanks,

 rikona