Hi Jimmy How you refinish depends entirely on how the pine was finished in the first place.
If the original finish was laquer (and many used this finish in the 60's), the surface will have to be sanded, and new laquer applied or, using laquer thinner, the old finished scrubbed off to new wood, then sanded and a new finish applied (like uretthane). If alcohol based shellac, the same procedure, except using denatured alcohol to scrub. If varnish or urethane, the surface can be sanded, old stains scrubbed with a strong cleanser, and two new light coats of urethane or varnish reapplied. If an oil (tung, linseed, etc), the surface can be scrubbed with a cleanser then steel wooled, wiped clean and two coats of oil rubbed back in the surface.