Prisms are very easy to open yourself. Most just have a few screws holding the top case on, they are usually located at the corners near the base or along that rim, sometimes underneath the base. You may have to peel up some leather on some to find em but some double sided tape will put it back in place like new again.

using denatured alcohol to clean the surfaces, a can of air to blow the lint off and the deed is done. Just watch for the silvering I see deteriorating in your prism indicated by the straight white line in your image.

If the smudge is not effecting the pictures why bother?