How long before resale/throwing away?

[myenia.livejournal.com]

How long should an artist hold an original (in my case, its a relatively cheap one) in wait of responses to contact attempts?

I have a ballpoint pen commission that I did as a take-home at AC, and have been unable to get in contact with the commissioner to obtain a shipping address. I've sent a note via DA, but it has not been answered in the last couple months, and I've found no other way to get ahold of them. How long do I have to hold on to it before it is ethical/acceptable to sell the original or otherwise get rid of it? When is it acceptable to remove the "not for sale" sticker in my folder for future cons?

I assume the smartest thing to do, if/when I do choose to do that, is to at least keep a digital copy.

The commissioner's character is named Janice, and is a wolf wearing roman soldier clothing. Anyone know this person?