Well, I was able to buy a "vintage" set of oils, and the tubes were pliable. I really don't know how old they are, but I can report that they work just fine. I also picked up some "vintage" Marshall's pencils, and they work fine also.
Now, I have another question. You recommend wiping down the entire print with PM Solution before starting to apply oils. I have a print on which I didn't do that. Now, the area where I removed some excess paint around the perimeter of a subject (using PM Solution) has a different appearance, especially when the light hits it in a certain way. It's not like a shadow, but it definitely looks different. I'm guessing that, if I'd coated the whole print in the beginning, this wouldn't have occurred. Should I try wiping down the unpainted areas with PM Solution after-the-fact? Or would it be easier to just spray the print with a clear finish? Thanks.