What should a Muslim do if he verbally mentions the name of Allah (such as saying: "Mashallah" or "Bismillah") over something he is holding? Is it permissible to enter the lavatory with it, or is it impermissible to throw it away?

The mention of Allah Almighty on a garment or the like, without the divine name (Allah), does not prevent one from entering the restroom with it, nor is it disliked. However, it is forbidden to enter with a Mushaf (copy of the Quran), and it is disliked to enter with anything else upon which the name of Allah has been written.