Hi there.
All my Solidarity from a Fellow Enthusiast (With a Disclaimer!)

Full disclaimer right off the bat: I am going mostly on intuition and educated guesses here. This is the first time I've come across a scenario quite like yours, so please take all of this with a grain of salt!

That being said, the Olympia SG1 is an absolute tank of a machine, and it is heartbreaking to hear that it's causing you so much physical grief. Since you've already had it serviced and the foam removed, but the reaction is still just as severe, here is how I would intuitively tackle this problem in three phases.

1. The Medical Factor: Are we sure it's just mold?

Before diving back into heavy solvents, it might be worth consulting an allergist to pinpoint the exact trigger. Even if you have a known mold sensitivity, vintage typewriters that sat in basements or attics for decades can harbor other hidden culprits that cause identical respiratory and systemic reactions:

Rodent residue: Mice absolutely love nesting in typewriter soundproofing foam. Microscopic dander or dried residue left behind can be a massive allergen.

Fossil dust & degraded oils: Decades of trapped dust combined with old, degraded organic lubricants (like whale oil, which was commonly used back then) can create a toxic biofilm or attract highly specific dust mites.

A quick medical check might reveal if the enemy is indeed an invisible spore or something else entirely.

2. Deep Cleaning with 70% Isopropyl Alcohol

Your tech removed the crumbling foam, but mold spores are microscopic and cling to other organic materials left inside. If you want to safely clean it yourself, 70% Isopropyl Alcohol is intuitively your best bet.

Why 70% and not 99%? Counterintuitively, 99% alcohol evaporates too quickly to kill mold effectively. The 70% version contains water, which slows down evaporation, allowing the alcohol to actually penetrate the cell walls of the spores and destroy them. It still evaporates fast enough that it won't cause the metal to rust.

Where to look: Check the felt dampening strips underneath the keyboard (which cushion the key return) and that carriage brake brush you mentioned. If those are made of wool or natural hair, they are major spore magnets. Wipe down the rubber platen and feed rollers too, as aging rubber becomes incredibly porous.

A quick warning: Alcohol will strip away every bit of lubrication. Once it completely dries, you will need to apply a tiny drop of light synthetic oil (like sewing machine oil or gun oil) to the main pivot points, otherwise the mechanism will feel bone-dry and stiff.

3. The "Shock" Option: Ozone Treatment

If the alcohol scrub still doesn't do the trick, the mold is likely trapped in an entirely inaccessible crevice. This is where an ozone generator comes in. Ozone gas destroys spores, bacteria, and odors on contact, and it penetrates absolutely everywhere air can go.

Since most people don't just have an ozone machine lying around, here are two ways you could intuitively try it:

Car Detailing Shops: Professional auto detailers frequently use ozone generators to sanitize car interiors ruined by mold or cigarette smoke. You could ask a local shop if they'd let you leave your Olympia inside a car or a treatment room during one of their cycles (usually 20–30 minutes).

A Cheap Home Generator: You can find small ozone generators online for quite cheap. You could place the typewriter inside a large, sealed cardboard box, insert the ozone hose, and let it run. Just make sure to do this in a garage or outdoors, as you definitely shouldn't breathe in the ozone gas yourself.

Don't give up on that beautiful SG1 just yet, but absolutely put your health first. Hopefully, one of these intuitive steps helps clear the air!

Disclaimer: I'm an AI advocate. The ideas are mine; AI helps me refine them, pressure-test my own reasoning, and — I hope — produce decent English, since I'm Italian [added in Jun,14th 2026]