mnnaj

I've been slowly rehydrating the urns.  I've burnished a couple.  @Callie Beller DieselI think I will remake them, less blocky looking.  But I do like the burnished effect.  This one has burnishing on the left and not yet on the right.  Also on the plus side, they feel smoother and less powdery.
Nancy

I've got two of the urns in my damp box, I did as @oldladysuggested and dunked them in water, (that was a bit scary) then put them in the box.  I don't have much access to the pottery lab over the summer - it's full of kids programs, so I'll try to slowly rehydrate them. 
I'm thinking once they are hydrated I could burnish them to help make them smooth and give it a bit of a gloss.  Life is an adventure.  It doesn't hurt to try. 
Thanks for the ideas @Rae Reich & @Callie Beller Diesel I had thought of car wax and dismissed it, but wax resist is an idea, especially if it is plant based.
Nancy

Yes, @kswan & @Bill Kielb, I do want these to break down in nature.  I had thought of beeswax, but not vegetable oil.  I have vegetable oil.  I threw them pretty thick, so I'm not sure how fragile they will be. I'm sure they will chip though.
I will take one of them and do as @oldlady  suggested and try to rehydrate it to scrape off the outer slip and bring out the colors.
One of my husbands friends wants his ashes to be sunk, dropped, submerged in a lake, so that is one of the ideas for this.  Hopefully I will not need to use them soon.  

Yes, @kswan & @Bill Kielb, I do want these to break down in nature.  I had thought of beeswax, but not vegetable oil.  I have vegetable oil.  I threw them pretty thick, so I'm not sure how fragile they will be. I'm sure they will chip though.
I will take one of them and do as @oldlady  suggested and try to rehydrate it to scrape off the outer slip and bring out the colors.
One of my husbands friends wants his ashes to be sunk, dropped, submerged in a lake, so that is one of the ideas for this.  Hopefully I will not need to use them soon.  

i do not understand the use of the word "degrade" in this instance.  if you mean scraping the surface to sharpen the contrast between the colors, you can test it by very quickly dipping  one of the pots into a bucket of water deep enough to submerge the whole thing.     yes, i know that your first thought is that it will break the pot.   if you use two hands and do it all at once,  the very dry clay will probably suck that first dip immediately.   yes, it will.   than you can cover it in plastic and spray it with clean water after an hour or so.    cover it again until you get it back to the right amount of dampness. 
scrape with a wide metal rib and you should be able to get the result you want.  this is not something to be tackled by a person who is hesitant about using tools this way.   it is probably easier to just make more of them.