Nevada
https://www.leg.state.nv.us/nac/NAC-640C.html
AC 640C.240 Towels, linens and gowns; single service items. (NRS 640C.320)
1. After a towel, linen or gown has been used once in a massage establishment, it must be deposited in a receptacle provided for soiled towels, linens and gowns and must not be used again until properly laundered and sanitized.
2. After being laundered and sanitized, all towels, linens and gowns in a massage establishment must be stored on shelves or in compartments, cabinets or sealed plastic containers that are used only for that purpose.
3. Any items designed for a single service and all towels, linens and gowns furnished for the use of a client must be clean.
Pennsylvania
https://www.pacode.com/secure/data/049/chapter20/s20.54.html
20.54. Linens.
(a) Massage therapists shall store single-service materials, including clean linens, in a manner that maintains their cleanliness.
(b) Massage therapists shall furnish clean and fresh for the use of each individual client single-service materials, linens and any other items, materials or tools that come into contact with a client’s body.
(c) Massage therapists shall place soiled linens in a covered receptacle or washing machine after use.
(d) Massage therapists shall wash soiled linens in a clothes washing machine in hot water with detergent and bleach after every use.