I would like to remove my Model 39's rear sight and clean and oil underneath it. What is the approved method of raising the spring on the sight so it can be rotated without damaging the finish on the sight or slide, and what is the approved tool?

If you have a padded bench vice, put the slide portion in the padded portion tightening it secure so the slide doesn't move, and with a round punch type tool (small enough to fit in the groove in the front of the sight blade by the ejection port0, carefully lift up the leaf portion of the sight just enough to clear the sight blade relief cut on the top of the slide. I have seen the leaf portion of the sight break by lifting it too high upward so be careful. Carefully swing the leaf portion towards the rear of the slide, until you line up the back portion of the sight blade base so that it will come right up/out of it's slide cut. Remember there is a spring and plunger under the back of the sight blade base which is the magazine disconnect so don't lose them. If you oil around the sight blade base you should be able to avoid much blue loss, and if there is some, cold blue on a Q-tip will take care of any blue loss. Hope that helps.

Thanks, Model 39. I ground a round end on a pin punch whose end had been broken off. The spring came up easily and after turning 90º the sight came off easily. There was incredible crud under it; so much that the spring and magazaine disconnector moved sluggishly.