Shanower provided a partial story in 1993: "The Silver Jug." The story tells of a servant of Glinda's named Amanda who isn't the best at her job by a long shot. While Glinda is away, she tests Amanda by tasking her to care for a wax-sealed silver jug. If it is opened, it must be sealed again by the time Glinda returns.
The following year found two conclusions to the story being printed in Oziana: one by M.A. Berg and the other by Fredrick Otto. Both involved the jug being opened and Amanda having to get help to take care of the result.
"The Silver Jug" did not use either Oziana ending, but instead, Eric wrote his own ending. Amanda frees baby dragons from the Jug and they fly across the Deadly Desert, Amanda pursuing in Glinda's swan chariot. However, they are eaten by a much larger dragon and Amanda decides that she has to take the dragon back to Glinda so she can explain what happened. However, the dragon needs to save a friend of hers, and Amanda winds up being the surprising key to the dilemma. Although Berg and Otto's endings to "Jug" were fine, Eric's is excellent!
The Salt Sorcerer of Oz and Other Stories is still available from Hungry Tiger Press, and several issues of Oziana are available from the International Wizard of Oz Club. (If you can't find the issue you want there, check used book sellers' sites.)
For anyone wondering, "The Two Peters" was reprinted in the 2011 Winkie Convention program book as part of the celebration of the 80th anniversary of Pirates in Oz. If you want a copy, contact David Maxine to see if he still has any copies left.