The bottom line with
DIY lens servicing is that, even with good mechanical skills and experience in fixing small mechanisms - without specific lens repair training, it's a 50/50 chance. You can improve the odds a lot if you can find some technical drawings or diagrams of the exact lens you're working on in the web (better yet if someone had posted a step by step thread or video). If you have a realistic expectation that the lens could get ruined, you can carefully dismantle it by trial and error and treat the exercise as a learning experience. It you happen to pull it off, then that's a bonus. If not, you've gained the knowledge of the inner workings and assembly for such a lens which could prove useful (for the next time?).
Prime lenses have relatively simple designs but they are all constructed differently and so have different dismantling procedures requiring different tools. Besides the basic set of jeweller's screwdrivers you can easily get for cheap at any hardware store, the other tools required can be expensive. If you can make your own special tools then good, but otherwise the cost of these specialist tools can be prohibitive for a one-of repair job. You'd be amazed how difficult it can be to remove a simple threaded collar (and how easy it is to strip the tool notches or dimples, and render it completely unserviceable) without a proper tool.
Spanner Wrenchs/Lens Tools
Lens Tools
Like Luiz mentioned, a 50-50 mix of household grade ammonia and hydrogen peroxide seems to be the preferred cleaning agent for mould. Lens tissue, a blower brush, and a meticulous eye is needed to remove dust during reassembly. I have no experience with the Zuiko 50mm but here's what a vintage CZJ 50mm looks like.
https://www.talkemount.com/f12/carl-zeiss-jena-tessar-50mm-1-2-8-nex-5n-927/#post5799
The dilemma we all face with legacy lens acquisitions is that, the cost of the lens servicing done by a professional can often exceed the price of the lens itself.
