I started changing Carto flavors by vaping a plain 10 nic PG juice after a flavor I no longer wanted to use. I usually can get most of the old flavor out that way. I even discovered that I like plain juice, It gives my taste buds a much needed break come mid day.
The PG Juice also cleans the cartos quite nicely since some of my favorite juices are VG which seems to gunk up my Cartos prematurely, so I'm actually getting 4 or 5 good days with 1 Carto now.
Sorry, I thought he meant cartos not carts. My bad...but still works well....