你可以用纸巾，并把用过的纸巾放进垃圾桶。

You might use tissues, and put your used tissues into the bin.

youdao

必要的时候才冲洗厕所：这意味着不要把厕所当成垃圾桶，不要将纸巾和虫子这些东西扔在垃圾桶里，避免浪费水。

Only flush the toilet when necessary: this means to not use the toilet as a garbage can: throw out tissues and insects in the trash (or even compost bin) to avoid wasting water.

youdao

用过后，请将纸巾丢进垃圾桶中。

Throw the tissue in the trash after you use it.

youdao