There is a big difference between something that "LOOKS" uncirculated and something that IS uncirculated, just like there's a big difference between a girl that "LOOKS" like a virgin and one that IS.
To be uncirculated the coin must have no wear on it. It should also have the original luster. Even if it has toned brown it will still have the cartwheel luster on it to be considered uncirculated. It can have "uncirculated details" meaning that there is no wear that affects the design, but it will be detail graded, meaning it is impaired. You should get some nice fresh uncirculated rolls of new pennies and go through them to see what a truly red unc copper coin should look like. Big difference in prices even between brown, red-brown and red uncirculated, let alone uncirculated, about uncirculated, extra fine, very fine, fine, very good, good, fair and poor conditions.
I posted these today for a gal to see that had a similar question. I pull colored coins out and keep them together in my color box. Always have. It must be toned metal and not paint or a contaminant on the surface or they then go into bullion rolls. I keep every thing! It might seem stupid to some. Two black beauties, two Wineys, an orange crush and a purple nerple. My names I give them. Image doesn’t show the colors well but you get the idea. It’s your Hobby do it how you want and have fun. Found these this morning.