I recently picked up an Olympus OMZ 50mm f1.8 pretty cheaply of ebay. The front element has a slight mould on the rear side although so far I've not seen this affect the image quality.
Disassembling the lens, the front three elements are part of one block. As on the parts diagram here:
How would I disassemble this to clean the rear side of the front element? I'm aware that it's not designed to be disassembled, and that it might be inadvisable to do it. But I'm very interested to hear what the best way to do this would be, providing the right equipment was available.