Does anybody remember using typing correction paper? I think it may have been called snowpake paper. It was like chalky white carbon paper. If you made a mistake typing, you aligned the mistake back in the typing space, slipped a piece of correction paper behind the guide but in front of the mistake, and then hit the same wrong key. If you were lucky, the letters aligned perfectly and you overtyped the incorrect letter in white. Then you could overtype it again with the correct letter. Fiddly, but neater and quicker than painting Tippex a few years later.