Huh, never had a problem with that. You gotta dry off the water after you’ve wiped them, to avoid lime spots from forming. Alternatively, you can use alcohol to wipe them down, which will dissipate without leaving spots.

But yeah, that’s about the whole secret. Just a cloth with water and then wiping all the surfaces of the window has always worked well enough for me. But I guess, your mileage might vary depending on what kind of grime is in the air where you live…