cleaning inside of convertible top?

I've been using ragtop on the outside, but what about the underside of the top? mines dirty as can be, but I dont have any idea how to clean it.

ttt

aw come on!

Talking about the headliner? I occasionally will vacuum mine with a brush attachment.

I just vaccume mine, how dirty can a headliner get? I never touch it so it just gets a little dusty.