संमार्जनोपांजनेन सेकेलोल्लेखनेन च ।
गवां च परिवासेन भूमिः शुध्यति पंचभिः ॥
sammArjana upaanjanena sekenollekhena cha ।
gavAm cha parivAsena bhUmiH shudhyati panchabhiH ॥
- manu smRuti
There are five ways you can keep the ground clean - by sweeping dirt off it, by smearing it with cow-dung, by sprinkling water over it, by scraping the top layer and by letting cows stand there.
- Manu Smriti