Hi Darren
Foam cleaner should do it. I use Servisol but they are all pretty similar. Be careful near any lettering as it can be quite aggressive. Incidentally I have a Shorrock Mk V in for repair and restoration at the moment that featured in this article
http://derbosoft.proboards.com/threa...960s-pic-heavy so I may contact you for some internal closeups when I get around to starting on it.
Regards
Graham