Good information SoucekFan.

​comma, I strongly recommend that you stick to mineral spirits, in particular the brand that SoucekFan has recommended, which apparently should be readily available in your area.

I often rub my finger against the sides of the typebars where they contact the segment, in addition to using fluid cleaning, to get some of the oxidation and remaining crud off. It makes a difference.

SoucekFan wrote:

I agree with the "getting worse before it gets better," but I think the OP should consider using a different brand of mineral spirits, because it may not get better. Jasco Odorless is the same chemical compound as Klean Strip Odorless, and it is different type of solvent--Hydrotreated light distillate--which is not the same type of mineral spirits as Varsol, which is a Stoddard solvent, the type that is generally recommended and was used by repairmen back in the day. From my experience, Klean Strip Odorless Mineral Spirits, which is the same chemical as Jasco Odorless, is goddawful for cleaning the segment and moving parts. I have used it on a fairly clean segment and it completely stuck the mechanism exactly like the OP; and it would not get better. That type of mineral spirits leaves behind a stickiness. It will gum up everything, and not just because it is moving old grime, but because it is lousy for cleaning moving parts. I believe you could immobilize a completely clean typewriter with that type of odorless mineral spirits.

I do not believe they sell Varsol in the US, and most of the big box retailers in the US (Home Depot, Lowes, Ace, Menards) only carry the Klean Strip/Jasco/etc odorless type; but Startex Paint thinner, found at Sherwin Williams is 100% Stoddard solvent type mineral spirits, the same as Varsol. From what I have read, Stoddard solvent is the recommended type. The Stoddard solvent is excellent. Before I discovered the difference between types of mineral spirits, I was confused as to why everyone else was getting good results. Now I get it.

This has confused me also. I've bought mineral spirits to clean oil paint off paint brushes, and I've found it to be a milky substance -- totally not what I expected. Works fine for the brushes, but I'd never use it on a typewriter because it seems to leave a residue and does not evaporate quickly. I may look for the Stoddard-type stuff, but I've found naphtha (or whatever is used for lighter fluid these days) doesn't harm plastic or paint, and is effective in de-gumming the mechanicals of typewriters. (It works quite well in freeing up sticky leaf-type camera shutters and other internal camera parts too, which is how I came to use it in the first place.)
 

I was told this morning by an employee that Sherwin Williams in Los Angeles (California rather) cannot carry the regular startex paint thinner, only the 'green' variety, due to certain environmental laws pertaining to VOCs. They also had mineral spirits but it didn't say "100%"....

I got some of green paint thinner and will see how it works today.

Results: inconclusive.
Bordering on inexplicable...

The SG1 is MUCH WORSE. Checked this mrng and keys that previously were unproblematic are now sticking. Some that were sticking previously appear to have improved.

However, the Royal QDL, which previously was unuseable, is in perfect typing order. ZERO sticky keys and before the application, ALL of them were gummed up and sticking in top position.

Very confused right now