Heavy on the dates!

In pen #1, crossed out with pen #2: Shareware summer ’92
In pen #2, crossed out with pen #3: English 141 homework (spring 93)
Added in pen #1, also crossed out with pen #3: + term paper 5/93
In pen #3, crossed out with pen #4: System files BACKUP, 7/93
Added in pen #3, crossed out with pen #3 and #4: , 7/20/93
Added in pen #3, crossed out with pen #4: , 8/93
In pen #1, crossed out with pen #1: Games from Kim
In pen #1, circled, in attempted wildstyle, heavily crossed out with pen #2: GAMES FOR KIM, FROM PAT, PLEASE RETURN
In pen #2: Math 390, fall 1995
Added in pen #1: + coursework backup

Then all crossed out with an almost-dry red Bic with a big X and the label CORRUPTED? getting squeezed toward the edge of the paper.

And building on what sincarne said, for maximum palimpsest authenticity, print out some fake commercial labels (BusinessPro for Professionals 2.4, Carnauba Ltd, (602) 555-1888, 230099 Birefringent Pkwy, Trimaran AZ 85058, Installation Disk 1 of 3, do not duplicate) on disks of brand-ish colors, then cross out or blank-address-sticker over them to make the user’s writing surface.

The one thing that would make this look like a fakey prop to me would be one neat label per disk in the same pen and handwriting: unless, of course, it’s made clear in-story that the person who owned the disks was profoundly troubled.