Dear Angelika,
Sorry to hear of your troubles with the Gremelius silver stain. The Gremelius 
silver stain is used in pathology to demonstrate carcinoid tumors (aka 
tumours!!) and has been largely replaced, at least here in the States by the 
Churukian method, and by chromogranin immunohistochemistry.
The Gremelius method is rather long and pH dependant. As with all silver 
stains, use acid cleaned glassware and triple deionised water. Get the pH 
correct. Use islets of Langehans in the pancreas as a positive control. If 
you get weak staining, you can return the slide to the silver to intensify 
the staining. The Gremelius method does require some patience, since it takes 
so long and the staining is often initially weak. I would be happy to fax you 
our method, but I think you will find its not a whole lot different to the 
published methods.
An interesting note is that at an NSH meeting a few years ago, Mr Churukian 
said the laboratory in Scandanavia (Sweden?) where the Gremelius was 
developed  was using the Chrukian method!
Good luck!

Mike Titford
USA Pathology
Mobile AL USA