This is a test of commonsense with single/multi-choices. Complete the next sentence:

How to clean rust off steel
Use a potato and dish soap on light rust.
Cut a potato in half with a knife. Drizzle dish soap onto the cut end of the potato.

1). Rub away rust by firmly scouring rusted areas with the soapy potato. This method can be messy; work over a sink or outside for easier cleanup.
2). Then, dab the rust off with a damp cotton cloth or potato masque and a rust remover. Use an ice cube for larger rust stains.
3). If there is a hard spot on the potato that is hard to scrape off, this should be enough to clean the rust. If it does not, repeat the process with another potato.
4). You will want to change the space around the cut edge every few months to keep it cleaner. Don't apply your potato or dish soap directly over a cut wound.
The answer is:
1).