If the customer is using cleaning products with harsh chemicals or any toilet sprays/room sprays, it will remove the protective coating and leave stains.
Chemicals will also cause the plastic to shrink and become brittle and susceptible to damage.
Sunlight can also cause discoloration and turn the bidet yellow. These causes are listed on the manual.
The customer can purchase a replacement seat or lid and should be advised to clean with warm water and a small amount of dish liquid. Care instructions are on the inside of the lid.