https://forums.linuxmint.com/viewtopic.php?f=47&t=186752
It took a few seconds to bring the desktop back, but it did work beautifully.
dconf reset -f /org/mate/caja/
dconf reset -f /org/mate/caja-open-terminal/
dconf reset -f /org/mate/desktop/background/
rm -rf ~/.config/caja ~/.gtk-bookmarks ~/.config/gtk-3.0/bookmarks
killall caja