Ive tried a few different products (inc Autoglym Vinyl & rubber cleaner) to stop my E91 creaking to no avail. But reading this thread made me realise I was attacking the wrong part; the main soft rubber seals (green arrows) on the door and body, when in fact the problem appears to be with outer discontinuous seals (red arrows)
I went out this morning and cleaned all these outer seals with a strong-ish mix of washing up liquid in hot water using a sponge and soft nail brush. I was careful with the felt bits. Then wiped dry immediately with a clean microfibre towel. I didnt go near the main seals (green arrows) at all.
Hey presto absolutely no creaks or squeaks all day. The car has not been this quiet for months.
I cant believe Ive wasted so much effort in cleaning the wrong bits with the wrong product.