There are two ways to avoid a Puppy picking up pup save files on a frugal installation.
1. Make a copy of your original save-file.
if original save-file is called lupusave-name.xfs
make a copy, calling the new one something like lupusave-name2.xfs
retain the basic naming convention lupusave-<name>.<2/3>fs
2. Reboot, Puppy it will give the opinion of which save-file to load, or the opinion not to a load save-file.
Depending on your installation, if you have the Puppy boot screen
it allows different settings to be used:-