New Construction Flooring and Tiling?

I am having a new home construction with a builder. When they did the sheet rock and plaster/mud, gobs of the plaster/mud got all over the bare concrete slab. They eventually sanded it all down on the concrete, but many areas have white spots from the plaster mud. I can find on many sites that before tiling the concrete must be level (which technically it is now), the concrete must be clean from dirt and dust (which technically it is now), and that the thinset must be able to adhere to the concrete (which I believe technically it can't on many areas of the concrete). But I can't find anywhere that specifically talks about plaster/mud and what should be done if anything, if it is still on the concrete. I'm hoping some flooring experts can weigh in here.