Canon FD 300/2.8 L disassembly

I have a Canon FD 300/2.8 L tele (white tube, internal focussing). The inner lens towards the camerabody is soiled with sticky gunk (may be from dead insects), and other odd stuff sticking to the sides (there is no filter in the dropin-frame). For cleaning I would like to disassemble the rear part of the lens, at least remove the turning part that fits to the camera body: This would facilitate proper access for a through clean-up without using long "sticks" etc...
Any advice how to start off and avoid tragic pitfalls is most welcome!
In case you're aware of a competent camera repair here in Nairobi (Kenya), I'd appreciate a hint, too.
Thank you in davance for any support.
Pitt

If you can take a picture of it, more people can chime in and help.

You probably need a lens spanner, which is more or less a special tool.
PRO TIP: However, a caliper (vernier caliper), filed as needed using a filing tool, can be a pretty good makeshift lens spanner.

The mount itself should be held on by several cross point screws.
As I recall, Canon uses a flexible circuit from the CPU to the body contacts.
Tear it and you have a REAL problem

John Koehrer said:

As I recall, Canon uses a flexible circuit from the CPU to the body contacts.
Tear it and you have a REAL problem

Click to expand...

This is about a FD-lens. No CPU involved. Not even electrical contacts.

Thank you for suggestions!
John's hint for screws made me dig, under thick paint I found 3 minuscule screws fixing a big retaining ring (see attached picture showing the ring).

As AgX stated, nothing electrical here, not even mechanical transmissions. The aperture is part of the stud.
I managed to disassemble this part - no issues at all, and easily clean and reassemble. Tool: fine 1.25mm screw driver.
Thus, the lens has an amazingly big image circle - certainly good for 6x7cm+...
In case anybody has more in-depth info on the comprehensive disassembly-reassembly of this lens, I'd be very grateful for sharing!
Cheers, Pitt.

AgX said:

This is about a FD-lens. No CPU involved. Not even electrical contacts.

Click to expand...

skipped the fd part.