An easy way is to make an image file from your cdrom
dd if=/dev/cdrom of=/tmp/cdrom.iso bs=512
(if /dev/cdrom is the one that is the one you use to mount, but don't mount it for this) But you will need to be root for this in most cases.
let it run till it stops with an read error.
this iso file you can burn again, this will be a copy at this
The other way depends a bit how the files are organised on the cds of your distribution.