The linen in the hotel is a little yellow after two years of use. What can I wash to make it white?

According to the specific situation, you can prescribe the right medicine.

If people bleach with hydrogen peroxide every time in the past two years, basically you can't expect bleaching to wash white.

If not, then oxygen bleaching or chlorine bleaching can be considered.

If it is because of the high content of iron ions in water, iron trioxide will precipitate and turn yellow for a long time, we can consider using oxalic acid to reduce ferric iron into ferrous iron through the reduction of oxalic acid, and then wash away ferrous ions through the complexing properties of oxalic acid.