Question: How to clean a bicycle helmet?
Option 0: Pour a few drops of dishwashing liquid in a bowl, add water, and dip sponge into it. Clean it thoroughly with sponge. Make sure helmet has soap everywhere then leave to air dry.
Option 1: Pour a few drops of dishwashing liquid in a bowl, add water, and dip sponge into it. Clean it thoroughly with sponge, then clean with cloth,  and leave to air dry.
Answer: 1