There are various types of soil:
- Dust
- Dirt
- Tarnish
- Stain
- Foreign Matters
DUST:
This is composed of loose particles deposited from the air. It contains both organic (human & animal hairs, dead skin cells, pollen from plants) and inorganic )san, dry earth) matter. Although dust is light, it is heavier than air and thus settles readily on any surface.
DIRT:
This implies dust hold together firmly by moisture or grease on rough surface.
TARNISH:
This is discoloration on a metal surface caused by a chemical reaction with certain substances found in air, water and food stuffs. There are different methods for removal of tarnish from different metals.
STAIN:
This is a discoloration caused on hard or soft surface by a substances containing dyes, proteins, and acid. Stains are difficult to remove by routine cleaning process.
FOREIGN MATTERS:
These may be dead flowers, contents of waste papers, baskets and ashtrays as well as stains.
NATURE OF SOIL:
- Organic soil
- Inorganic or Mineral soil
- Osmological soil
- Bacterial soil
- Entomologial
ORGANIC:
A substance that has a plant or animal origin. Organic compounds essentially contain the elements like carbon, hydrogen and oxygen.
INORGANIC:
A homogenous chemical compound, solid, liquid or gaseous substance, having a chemical composition resulting from the inorganic processes of nature.
OSMOLOGICAL:
These are the substances containing either organic or inorganic matter that emit an unpleasant odour.
BACTERIAL:
Some soils may contain live bacteria or their spores, which may cause diseases or infections.
ENTOMOLOGICAL:
These soils harbor insects, especially those that are carriers of disease and infection.