1. all shutter repair instructions and manuals state that the aperture and shutter blades be dry and free of oil and grease.
2. lighter fluid leaves an oily residue and will damage or destroy plastic and rubber parts. Plastic and rubber parts have been used in shutters since the 1940's.
3. Lacquer thinner is an excellent degreaser but will strip protective coatings off the aperture and shutter blades as well as damaging or destroying plastic and rubber parts.
4. denatured alcohol is in the same class of potentially harmful solvents to be avoided in shutter repair.
5. CRC QD Electronic Cleaner,
Dead Link Removed , is an excellent degreaser/cleaner that is safe on plastics. Other brands of electronic cleaner may not be as good such as the one sold at Lowes. I spray it into a jar and let heavily gunked up parts soak for a while.
6. Grease is oil suspended in a soap base. Grease allowed to sit unused for a long period of time will have the oil separate out and the soap dry out. Sometimes the dry out is only superficial and exercising the piece of equipment will bring it back to life other times it won't.
7. Extra fine powdered graphite used by itself is an excellent lubricant for aperture and shutter blades. I rub it in with a cotton swap being careful not to bend the blades, get it into the pivots, and remove any fibers left behind.
8. The shutter is possibly a Compur. Although the exact camera this thread is about is not listed other Voigtlander cameras are.
http://www.suaudeau.eu/memo/rep/Compur-shutter-repair-manual.html
Compur, Compur Rapid, and Synchro Compur are very similar in build design. There are only a few Synchro Compur shutters and numerous variations that are merely adaptations to the many makes of cameras they were used in.