ᐅ Removing adhesive residues from exposed concrete ceilings

I could cry and really hope someone here can give me some advice.
We have modern exposed concrete ceilings on the ground floor of our house. We masked them ourselves for the plasterer using plastic sheeting and painter’s tape. Then, quite cleverly, we thought we might as well leave the masking on for the painter too, so they wouldn’t have to mask the ceilings again.
Unfortunately, the painter didn’t come until more than a month after the plasterer...
Well, last week—now that the painter has finished—we removed the plastic sheeting, and I almost had a breakdown: the tape left unsightly marks on the exposed concrete ceiling (see photo above). Unfortunately, these marks can’t simply be rubbed off. It seems as if the adhesive’s solvent penetrated the porous concrete. Even my husband’s attempt to lightly sand the ceiling only made a minimal difference. What now?! I’m hesitant to try any common adhesive removers on the ceiling because I’m afraid the oils they contain could cause even more damage.
I’ve searched online extensively, but somehow no one has been able to help. Maybe someone here has some advice?! It just can’t be true that we’ve ruined our new ceiling because of this carelessness?! I’m grateful for any help!

Have you ever called a mason or concrete supplier to ask?

Regards, Yvonne

My standard precast elements used as the base/formwork for the reinforced concrete ceiling looked the same. Is "exposed concrete" any different in this regard? We tiled and painted our ceilings, so you don’t see anything like that afterward.

The concrete is meant to be visible! At this point, it’s best to consult a professional before attempting to make improvements yourself and potentially making things worse.

Good morning,

take a look here: https://www.hausbau-forum.de/threads/sichtbeton.4931/page-2#post-71547

Maybe you can benefit from the experiences of the user "One00"?

Regards, Bauexperte

Yes, exactly, the concrete is meant to be exposed and is usually not further treated or processed. We specifically paid for fair-faced concrete quality, so completely new formwork panels were used to achieve as uniform a surface as possible. Unfortunately, our contractor doesn’t have much experience with exposed concrete yet. At least he couldn’t offer us any advice. Experts in this field seem to be quite rare. I even contacted the tape manufacturer but haven’t received a reply so far...

Wow, “One00” really took a risk – mixing paint directly into the primer?! I think my husband would definitely object to that. It might help to some degree, but since some of the taped areas are already quite dark, I’m afraid the joints will still be visible.

Thanks already for the responses, and if anyone else has any ideas – PLEASE share!