Use them to clean. Old T-shirts actually make great rags - you can use them for dusting, washing the car, etc., then wash and re-use.

把他们洗洗干净。实际上旧T恤当抹布不错的，你能用他们抹灰，洗车，等等，之后洗干净，重复利用。

youdao

If there are more tenacious spots to clean off, you can use a wet rag to rub them clean.

如果有顽固污渍的地方需要清理，你可以用块湿抹布擦干净。

youdao

Now, we have to shave our heads to keep them clean without the use of water.

现在，我们必须剃光头，从而在不使用水的情况下保持清洁。

youdao

Water quality issues also create risk for companies, from stricter pollution standards on their own effluent to other entities polluting water upstream, requiring them to clean up water prior to use.

FORBES: A New Tool To Manage Companies' Growing Water Risks

The introduction of rehydration salts 20 years ago had had a significant impact, he said, but again there were problems with access in developing countries, where there was also no guarantee of clean water to prepare them for use.

BBC: Virus is devastating in the developing world