What is this stain and how to remove it. On site now

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I do quite a bit of new construction cleaning of garage floors and driveways. About 150 so far and my first time running into someone who wanted more than what would come off with water and a bit of pressure. This driveway had a few spots that the new owner wanted removed and I think the builder or painters did something here. They want this bright spot gone.

Also this red chalk stain. I only have f10 and my surfactants, and some gutter grenade. Thanks!

Don’t mind the wet spot on the first pic. I live in the PNW :slight_smile:

Another view:

2 of them.