How do I open up a Rolleinar 2 close-up lens to clean?

[xkjag]

I have 2 Rolleinar 2 close-up lenses both with fungus inside the front part. The rear component simply twists off, that leaves a front and rear element in the front part. I believe the front black retaining ring can be unscrewed using a rubber mat on some of these but some are glued in, I think mine are too, they won't unscrew with a rubber mat. The threaded black retaining ring in the rear has two notches that sit below two notches in the housing. I was looking at the lens wrench tools for sale on ebay - I don't expect any of these will work on this because the notch needs to be turned underneath the housing and all those tools address the notch vertically. I need a tool that addresses the notch horizontally so it will move under the housing. Does anyone know what kind of tool I need for this? Thanks, Pete