How to clean this Helmet? My son has that helmet for bicycles. Its brand new and was gifted to him recently. Unfortunately due to my mistake it was left in the backseat of our car and has accumulated some dust/lint which is making it look dirty.

I want to clean it but don't know how, I don't wish to ruin it by just trying with a wet cloth. Its surface texture is like a very high quality tennis ball and it's not the carbon fiber hard top ones that I'm used to.

Any help would be great, That helmet is beautiful and I don't want to ruin it in haste.
I'd run it under a cold shower if the lint roller suggested in the comments (or not too sticky tape) didn't work. A helmet that can't take a cold shower can't take rain and is therefore useless unless you live in a desert (which Sweden, where it apparently comes from, isn't renowned for). 

One further thing to try is a vacuum cleaner with a soft brush attachment. Ideally you'd use reduced power or open a vent hole so you don't suck too hard.