Thanks, Mike, you have some good points.
I assumed that a close-up view of the backplate would be sufficient to determine the model of Jose's capsule.
I agree, removing one of the four big screws might seem scary to the novice, though no real damage to the capsule should ensue, unless you slip with your screwdriver, or get into a raging fit of frustration.
To you question: After removal of contamination of the kind seen on Jose's capsule, return to factory performance can be expected in most cases. But only professional cleaning, (professional underlined!) will leave the sputtering intact, and avoid introducing additional contamination which could infiltrate the space between diaphragms and backplates.