While Zippo lighter fluid (Naphtha) is a bit more expensive per ounce than other solvents (mineral spirits, lacquer thinner, et al), it does usually come packaged in a dispensing container that may make it easier to dispense in a directed method into the internals of typewriters for cleaning them out.

The other benefit is that some may have it on hand for general household use without needing to make a separate trip to the hardware store.

via, but not really directly suggested by https://old.reddit.com/r/typewriters/comments/1g9ntnj/lubricant_reccomendations/

The case FOR WD-40 use in typewriters by [[Thom Cholowski]] in Antique Typewriter Maintenance Group

Some thorough colloquial and unreferenced, but reasonably scientific advice about the use of WD-40 to clean typewriters, particularly with respect to water displacement.

Once used for cleaning typewriter internals, WD-40 needs to be flushed out with kerosene or naphtha.