Alan,
I'm not sure if it will work but you could try the colorfill solvent.
http://cgi.ebay.co.uk/Colorfill-Solvent-/270647887577
It's the stuff that's used to remove excess jointing colorfill glue when joining kitchen worktops. It works a treat on that glue.
You could also try this stuff.
http://www.diytools.co.uk/diy/Main/sp-2-12124-97094-everbuild-stick-2-superglue-remover.asp
Jeff Hooper
January 2011