Steve,
I always wonder what someone does when they say they are going to "clean it up". I would not do anything than give the metal a bath with Hoppe's No. 9 solvent and light work with 0000 steel wool. A good rub down and a light coat of oil. I would not use the old shells. I would order some 2 1/2" shells from RST
www.rstshells.com and be a happy man.
Great looking Parker and please don't do to much to her.
Kindest, Harry