My Smith 36 I bought when they still cost $68, that's bout 50 years ago. I just about ruined it by squirting WD40 into the works at the lifter. Now it's pretty gummed up in there and it kind of sticks. I'm not taking it apart though. I just deal with it. But I'd never squirt WD40 into the guts of any gun today. It hardens and things don't work as smooth as they did when new.
If you watch the video link I posted a few posts up it walks you through every step. It's not hard at all and if I were you I would open it up, scrub the wd40 out, and re-oil the parts.