Shutter/Aperture consists of 3 fragile pieces and 3 tiny washers. Make notes to put them back in the correct order and orientation (see 2nd picture). The washers keep the shutter pieces level.

Last picture from another camera showing how bad the oil residue can be. Probably due to usage of wrong oil. Clean and dry everything with IsoPropylAlcohol and a microfibre cloth. These shutter parts DO NOT need any grease or oil at all.

If you want to grease other mechanical parts, make sure to use finest, resin-free oil (no WD40 or similar).