Return an artifact to Rum's Spring and you receive the Magic Stones you offered for it,
and that artifact can be drawn again.
Magic Stones spent on upgrades are returned too.
This button opens the Return tab.
Use ↻ to change the item a return consumes.
Returning with Rainbow Crystals costs more as the number of artifacts you hold grows,
but Ancient Restoration Dragon Sand returns an artifact for a single piece however many you hold.