There is a public laundromat in Krakow (ul Dietla). I use it and so do many other people. You can leave your washing there for a service and pick it up later. It has a bar where you can have a drink and relax.
It is attached to a small hotel, so has plenty of business from students/foreign visitors.
As for this unbelievably stupid thought that I don't want to wash in a public machine in which someone else has washed their clothes the answer is simple - wash at 100 degrees -it kills al known germs.
I suppose those peculiar people will never ever use a public toilet - because someone else sat on it before you and we can only imagine what they did. There are more germs on a public toilet seat than there ever will be in a washing machine.
there is a laundromat on ulica Dieta in Krakow every time I have passed there is no one inside.
...Have you actually been in? Have you ever done your washing there?
The washers and dryers are going like the clappers all the time.
The girl behind the bar is always doing service washes. The place is busy.
Not everyone has a washing machine. In my case I don't want one as yet, as I'm only in Poland for a few weeks at a time.