There could be a slight appearance of black “stains” on the rectangle to make it seem even more real, but disregarding that they pretty much look identical.

I accomplished a similar appearance by scribbling barely perceptible lines on the rectangle which represents the faint lines you can see on the square. I also added a slight gradient to the faces of the rectangle which were there on the square along with a few other things.

I added a slight yellow tint and reduced saturation to make the color as similar as possible the real thing, and then after that i reduced the clarity to make the differences between them less visible, dehazed to make it look even more realistic as well as grain for the same purpose. I was originally gonna go with pixelation instead of grain, but that made it look drastically different than the real thing.

The struggle

I don’t exactly know what it is but real life has this effect to it that is unimaginably hard to replicate in stick nodes

Not gonna give up any time soon though