You can try to use a scrapper. Just be careful not to scratch the tiles. If that doesn't work try placing a wet towel on the grout letting it sit. It might soften it up.
Every time I clean my mirrors, they end up having tons of streaks and almost look worse than before I started. What could I use to clean them that won't leave streaks...
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I would try goo gone let it sit and then a scouring pad,
You can try to use a scrapper. Just be careful not to scratch the tiles. If that doesn't work try placing a wet towel on the grout letting it sit. It might soften it up.