If you are using multisession saves and the list of savefiles begins to get long it is easy to cut the number of multisession files own to two by booting the multisession system then moving all of the multi-session files off the usb (or even just deleting them) and click the Save-Session icon.
I can confirm that this still works as documented here:
https://oldforum.puppylinux.com/viewtopic.php?t=116147
https://oldforum.puppylinux.com/viewtop ... 56#1028256