Bugis Keris?

[A. G. Maisey]

There are various types of paint, and various ways to remove them, if you can identify the paint type, you simply use the appropriate paint remover.

However, if I was going to remove the paint, I'd use heat to blister it, then scrub off with a hard brush and mineral turps. After that I'd go over the blade carefully using magnification and a sharp pick, something like a saddlers awl, and make sure there was no paint left in the cracks. Then probably several soaks and rinses in mineral turps and a drench with WD40.

If you intend to go straight to a stain, you could use a vinegar soak after the paint was off, and omit the WD40.