Olympus oily aperture 50mm f/1.4 OM

Olympus 50mm f/1.4 OM Manual Focus Lens Repair.
Try this before you pull the aperture apart in your lens. It may be a simpler fix in the mount. This is not a guarantee but a quick check. If you see oil on the blades then you will have to pull the aperture. However this might be a simple fix.
Many Olympus lenses do get oil leakage into the aperture but from my experience about 7 out of 10 time it’s just the mount mechanism. The grease gets old and sticky and can cause the parts to be sluggish or stick entirely.
If you clean it and it is still sluggish then it might be needing the next step of pulling the aperture out and cleaning it.