Cleaning
If you don't know how to take a precision sight apart, it is probably better to leave it alone.
That said, it would appear from your post that the sight is dirty, gummed up and needs cleaned off so that you can see what you have and if it is operable.
Go to one of the Auto Parts stores and get a spray can of Carburetor Cleaner or Brake Cleaner. Take everything outside, wear rubber gloves, use an old pan or such, and spray the sight with the cleaner. Do not inhale the fumes and try to keep it off you, the lawn furniture and the Dog.
Use an old tooth brush to loosen up the crud after the first application. You will probably have to repeat this a few times, until you can easily turn the knobs for elevation and windage. Do not force the knobs as resistance can damage the sight.
After getting the adjustments to work, a light oiling will help preserve the sight and make adjustments easier.
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