Thanks El ZorDack, I removed the paint of these models by submerging them for a while in Dettol Antiseptic Disinfectant Liquid, which is an amber-coloured fluid, and then brushing the paint off with an old toothbrush.
Here is a sample of the type of paint job that I had to remove from these models. They did not look too horrible on the table and I still don't mind the scheme, but they certainly weren't quite photogenic.
This rejuvenated model features a new top-knot from the old chaos marauder kit, and a new radar as the old one was damaged in the stripping process.
[spoiler=]While it is a minor system, I still don't understand how we were unable to detect anything for so many generations while we were exploring and populating the surrounding sectors.
Cheers for looking =)