Just a suggestion...since DMR members are only allowed to enter one code per title / per format...if you are not sure what the code is from you may want to list it as a mystery or random code. As a general rule you will not receive as many bids on an unknown code since the buyer is taking the risk that they will not be able to redeem it and thus have to go through the hassle and fees of re-listing it.
Also, I have gotten into the habit of writing the title & format on each code sheet as soon as I open it, especially if I don't redeem it right away. Then, I also write on it the date that I redeem it. Otherwise, I'd never be able to keep track, especially with a little one in the house! Good Luck.