Hi Per.

Nice little watch you have for a birthday present :)

Personally, I would get it serviced and not worry about cleaning - it deserves to wear its age well after so long. Maybe get in touch with Jasper at http://www.classicheuer.de/ for servicing.

I'd probably put it on a simple black leather strap (unperforated), as it is shown in the original catalogues. Not crocodile, that would be too glossy for the dial. My second choice, given how the lume has aged, would be for a tan coloured leather, maybe even ostrich. With same-coloured stitching or perhaps black, the white stitching we've seen of late on brown straps would stand out too much for me and distract from the watch, rather than complementing it.

Mark