Watched it on YouTube.........best thing to use is a sponge! You can actually buy them on Ebay, I have one for my Drone if I want to record sound.
http://www.ebay.co.uk/itm/5pcs-Small-Mic-Microphone-Windscreen-Soft-Foam-Mic-Cover-Sponge-Skin-35x10mm-/371231421024?pt=UK_Sound_Vision_Microphones&hash=item566f1df260