I have the Toto Washlet 300. We clean it with soap and water. One of the very nice features of the Washlet is by pulling two tabs the whole toilet seat assembly simply pulls out. I have had this for about 6 years and it hasn't deteriorated at all. I do not want to use any harsh chemicals on it as I would expect to see the plastic deteriorate.

As to the use of the appliance, I love it;) I shave my head and find that a wash and dry on the other end is just fine!

We have a Toto as well, and the plastic seat looks awesome now as before. So it's not true that all plastic seats deteriorate. Having said that, if you have a Toto, then please check manual and care instructions carefully since it is important to follow them to keep your toilet flush well.

I use Clorox or similar wipes to clean the seat and lid. I use an old toothbrush and Greenworks spray cleaner on the wands.