New concrete stained how to clean it?

[Brimaster]

The new building we had built is pretty much done other than the overhead doors. When I got home today the kids went down to ride their tricycles in the new building before daddy's "****" is inside and the damn birds decided to leave their mark on the new floor and the kids tricycles.
Tried a few things to get the mulberry stains up but nothing really worked.
I have an e-mail into the concrete coating guy but I was wondering if anyone have any ideas how to get this off the floor without screwing up the concrete?

 

[thegarageguy]

Very tough to recommend something without seeing it in person. It's more than likely that its permanently stained. This is why we always seal stained concrete.

 

[TONE]

I dont think he has "stained" concrete.............

I think he has "stains"........as in not wanted marks

Very tough to recommend something without seeing it in person. It's more than likely that its permanently stained. This is why we always seal stained concrete.