Top tip from a top rider (not me)
 

Tuck a piece of heavy duty tissue under your peak i.e. jammed in between you peak and your helmet, then if you need to clear your goggles you can do it while riding/racing.

I would do that but I just use tear offs. That would be good for just trail ridding thoe. THANKS!!!

For racing offroad, I avoid tear offs as littering in the woods is never a good idea. I use Scott roll-offs, and they're great!

plus you get like 40 pulls on a set of roll offs don't you??

You do get loads of pulls on tear off's but if I get mud below the strip it drives me mad and I have to clear it.

I use a neat little device from Scott, called the Mud Flap. You use it with rolloff system. It sticks to the lens of the goggles, then the rolloff film is slid under the mudflap, this keeps the water from getting under the film and smearring across the lens when you go for a pull. Of course you still need to water proff your helmet with duct tape and some foam.
From if you take a look at the photo that was taken on the 1st lap of a harescramble, I used the same goggles for the entire race, with no water problems.

http://cssphotodesign.com/gallery2/m...geViewsIndex=1


Here is a mud flap:
http://www.motorcycle-superstore.com...c=2&zmap=11634

http://cssphotodesign.com/gallery2/m...mId=1873480&g2

Got to love those self cleaning GoFaster stickers.

That was about the only part that was mud free!! GoFaster!!