Many of these pre-war Retinas were stored over the years in damp or otherwise improper way. As a result many have balsum separation which causes cloudiness in the lens. It can be fixed but is a rather expensive job.
There are still a number out there that have clean/clear lens and can still be found cheap..
The Lone Star State....
Leica M2 | M3 x 2 | IIIa x 2 | IIIc | IIIf black dial | Kodak Retina IIIc | Kodak Retina IIIC |
The only copies of this particular Retina (Type 142) I have seen for sale in the last two years with out a fogged lens were made for the European market. While this problem occurs in some cameras, I have never seen it appear in apparently every copy. I know some Leica lenses have the same trouble.