It needs washing once. In order to prevent the bed sheet from fading and remove the residual formaldehyde on the fabric, the new bed sheet should be soaked in salt water for half an hour before being used for the first time, then washed with clear water and dried. Do you want to wash the newly bought sheets? This is not just a simple cleaning problem, but an important problem related to health. Please don't bother. People who don't know enough about formaldehyde should realize that formaldehyde left on the fabric will be released from the fabric, which will directly affect health, cause diseases such as cough or allergic rhinitis, and even cause cancer. When looking for the answer to the question of whether to wash the newly bought sheets, I found that formaldehyde was added in the production to deal with the folds of the sheets. Although some cleaning treatment will be done before leaving the factory, it is inevitable that there will be residues, so it must be cleaned before use.