There's more spots than just these but these are the ones that are most visible. And I used 511 Impegnator sealer, which was what was recommended.

I answered on the duplicate post. Delete that one please. I have had great success with The Pink Stuff on multiple surfaces, including tile.

Nots ure why you ised a sealer of glossy glazed tile. Could it be a spot where thes ealer didn't get?And you do know how abrasive magic eraser is don't you? will take the glaze off a tile. If I had to guess Iw ould say you have removed the gloss from some of the tile and the "spots"a re areas that are slightly depressed and didn' get the glaze dulled with the eraser.

I had to seal them, since they are crackle glazed. Everything I've read about that type of tile stated that it needed to be sealed, especially since it's going to be around food, water, steam, etc. The hairline cracks would allow things to seep in otherwise.

The Magic Eraser didn't take any of the gloss off, those dark spots in my pictures were there on their own, nothing I've used on them in the past day made any changes to the tiles appearance.