Development of rust is due to present of three things. The steel, oxygen and moisture. To explain: metal rusts when exposed to oxygen and moisture, a chemical reaction. This is very common on steel nails and screws. They should be lead coated but manufacturing companies barely do it to cut on cost. Rust prevention is now the responsibility of handler, the middlemen and ultimately the customers.
1) Keep them clean and dry.
2) Store them in a clean, dry and tightly capped bottle. Keeping the moisture and oxygen away will definitely prevent rust.
3) Application with thin coat of grease or engine oil will help. This will serve as barrier against moisture and oxygen.
4) Buy materials just enough for your needs. Therefore, rust prevention will be seller’s responsibility.