Previous entries described tested options for the data. Unfortunately there can also be personal information on the label side of disc which must be removed.

During this digitization project, about 150 discs had personal information on them, like names, years of graduation etc.

I had the discs classified into groups based on physical properties of labels:

1. No writing
2. Marker writing - about 140-150 discs
3. Stick-on labels - 5 discs
4. Lightscribe/Labelflash - 4 discs

Simplest to remove/process are the stick-on labels - some minutes in water and they just come off easily, paper labels to recycling. Only had several of these, so no problem.

More interesting are the marker labels. Oldest discs were from 2004, making them 20 years old now. Tried chemical solvents - isopropyl alcohol and acetone to remove the writings. Worked ok for removing the actual marker paint. Acetone being more aggressive did a quicker job. Used some cotton pads as a wipe. But this made an inconsistent result, was quite messy overall and toxic chemicals were involved.

Biggest issue was the fact, that even after chemical wiping the original markings were etched into the label layer of disc, making the information readable even after the marker paint was removed. This was not good.

Really efficient way that I found to work is using 800 grit wet-and-dry sandpaper with water. Most discs required minimal effort to "sand-off" the markings even without chemically treating before hand. For around 150 discs I have used about half of A4 sheet of sandpaper. No chemicals needed and light sanding of label side keeps the actual data layer intact. Below is an image for how the text looks like after only wiping.

Lightscribe and Labelflash markings can also be removed by sandpaper, but the labels has a protective layer, which makes the process more labor intensive. Go with sandpaper if only a few discs.