Can dirty underwear pass the security check

Dirty underwear can pass the security check, but I suggest you bring clean clothes as much as possible. Security inspection is mainly to check whether there are dangerous goods or contraband in the articles carried, rather than to check the cleanliness of clothes. However, if the underwear is too dirty, it may cause disgust of security personnel or discomfort of other passengers, so it is recommended that you ensure that the underwear is clean and tidy before going out. If you encounter more detailed safety problems, you can consult the relevant regulations of the airport or related airlines.