No self respecting window cleaner could live without linen scrim: A very open weave linen cloth, like gauze.
Use with white vinegar for cleaning windows, picture glass, mirrors, drinking glasses and your specs, of course.*
Launder before use to soften and then hot wash to keep it grease free. Those converted to its smear free cleaning will settle for nothing less.
Increasingly hard to find... but they're back again by popular demand.
They measure 70x70cm but will shrink in the wash a bit.
*Top tip: if you CBA to do the housework but your place needs a sharpen up, just do all the glass - pictures and mirrors. You’ll be amazed how much better the whole place looks…