Take care about new Memorex CDRs. Some different packages LOT, this moment are not reliable in burning ,due maybe low cost manafactured.
Some info of factory and package made , take from :
(or in my opinion try find 48x discs in jewel case or 52x spindle of 25discs (made by Prodisc)-I have bought them in the past and they are very good CDRS but a little expensive I think !)
Also read this :
BTW Memorex (TY) seems stop be available any more ....