It comes from the factory pretreated so as long as you just rinse it off, do not use anything like DAWN as a cleaner, but rather a soft brush and some water should take care of most of your cleaning needs.
The many rag top Porsches I care for only get washed once a month. The other 3 weeks they get dry brushed and vacuumed when needed.
Bird poo gets taken care of on a spot cleaning basis.
When you need to retreat it then let me know and I'll tell you what to use.
I wash mine with regular car wash soap every time I wash the car. I always use a clean cloth and fresh soapy water, I wash the top first. I had the original top until 2 years ago, and it was starting to get pinholes in it and worn around the edges, but it was still clean looking.
A friend of mine has a 96 with a white top, they use GoJo orange and a brush for dirty spots. I have used that too, they tend to get dark lines where they fold if you put your top down a lot (which I do).
one thing I ALWAYS do now, is when putting the top down... stop mid-way & pull the top fabric out of the scissor-joint. This way, it won't get pinched & leave cuts in your top. Also makes for a slightly lower stack height for the top as well. As for cleaning, I've heard from multiple sources to NEVER use bleach, bleach-water, tire bleach, etc. on the vinyl tops as is weakens the threads & fabric. Have tried several supposed cleaners... Meguiar's vinyl cleaner works pretty good. Just picked up some RaggTopp vinyl top cleaner... will see if it is any better. Unfortunately, I have a WHITE convertible top- which is just about the worst to keep looking good.
I use a soft nylon brush with the cleaner. I apply the protectant by spraying the cloth, then wiping the top.
What surprised me was the first time I washed the car afterwards. I have a white terrycloth-covered sponge. Just wiping the top it came away showing a LOT of dirt. Good to know that it was being kept from the top.