I have a problem with my film negatives. There are some odd white spots on it. I got my film developed at a local place, and I've been going there for some time now so it's not a problem with them.

Once I got the film i decided to wash it because it had lots of dust on it and I thought that would be a smart decision. I used soap too which I think is what's causing this problem.

Now, whenever i rinse the film under water (I've done this like 5 times now), as the film dries off, it seems to leave these odd white stains / spots wherever it takes the water a bit more time to dry off. Has anyone had experience with this? Is it the soap or the water?

I can't really find any similar spots on the internet, and they're not consistent (each time I rinse they don't show up on the exact same spot). Also, some parts of the film don't get any stains, but most of the film does. Thanks!