Been there, done that, and gave up.
I opened my Tamron 90mm f/2.8 macro "just for fun" when it stopped working (lens wasnt anymore under warranty and totally unusable anyways, now its my paper weight).
After taking the bayonet mount off, I couldnt get further simply because I would have destroyed everything in the lens.
If your lens has dust and it wont show up on images, do not open it. If its visible in images get a professional to take care of it. Good luck!
You are what you eat - I dont remember eating a photographer.