Sticky tires

When I was at the track in Vegas they were spraying something on the track to aid in traction. What was that? At my local track they DONT use any and was wondering if there is anything I could use to make my tires stickier.

The product they use is called VHT. It's available from VP fuels. www.vpfuels.com

It doesn't help much with street tires but it works great with slicks.