https://www.mohawk-finishing.com/products/wood-touch-up-repair/fillers/fil-stik-putty-sticks/

Putty sticks (aka paint sticks) are good for filling in nicks and dings on furniture.

These putty sticks and some crayons are also great for restoring the colored index lines on typewriters as well as other colored metal parts and occasionally on some plastic typewriter keys.

M231-10104 SYY Red<br /> M230-0054 Crimson Rose #SN292<br /> M230-0046 COCONUT, COTTON, BRIE, HEAVY CREAM, SNOWFLAKE <br /> M230-0090 Picket Fence

Yanni Giftakis recommends melting crayons into the letter groves of typewriter keytops to replace their missing paint with a heat gun, much the same way D&D players will fill in the groves on their dice.

This is similar to Richard Polt's recommendation "To restore faded paint on keys and scales, try Lacquer-Stik Fill-In Paint."

via https://www.facebook.com/groups/typewritermaintenance/posts/3831371387100282/