I had a similar issue but not with an iscorama( it was a dyaliscope junior 16) and was able to successfully re-grease it on my own with white lithium grease. It was a little nerve racking though and the hardest part was putting everything back together properly, but it really wasn't that difficult. There are some threads on this forum with advice for doing it. Definitely wouldn't do it unless you are good with this type of stuff though, especially if you paid a good bit of money for your lens.