remove plaster stuck to basement floor

Hoping someone can help. Just had two bedrooms built in my basement. Outside of the rooms there is an area about 16 square feet. The contractor was not careful and plaster stained the painted basement floor in this area. One of the builder's employees scrubbed on it for a long time with Krud Krutter, Easy Bam etc..., but there are still essentially flat stains all over this area. Is there some kind of solvent or cleaner that will allow me to remove these stains? Thanks.
RL
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A mild acid may release the remaining plaster. Are you sure it is plaster and not drywall compound? If it is drywall compound you may just need more scrubbing, I don't think the acid will help much. Whatever it is, you will have to repaint the floor, as all the scrubbing will have changed the texture and any materials in the pores of the concrete may never come out.

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Thanks. The contractor said it was plaster and it does appear to be. I will probably try the mild acid approach after some more scrubbing and see what happens...
RL
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Klein-4 wrote:

You'll need more than a mild acid. Use a reasonable one for sufficient time and no scrubbing will be necessary as the acid will eat the gypsum (plaster). Repainting will be necessary.
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dadiOH
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Thanks. I'll look into this also.
RL
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I recommend scrubbing with a loaded paintbrush...
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Have you tried white vinegar?
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Regards,
Doug Miller (alphageek at milmac dot com)
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On May 24, 12:19 pm, snipped-for-privacy@milmac.com (Doug Miller) wrote:

No, I'll put that on the list. Thanks.
RL
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