for clay.. water is very important.. it depends on the status of the track right now.. is it settled in?? and drivable??
for how to water (if you obtain water) water lightly first.. let is sit for 30 minutes.. then water heavily.. it will retain it's water very well and as it cools down.. if you're racing at night.. the water comes back up and keeps it tacky..
if you can't water.. you sweep.. use a regular shop broom.. or 2 or 3.. with helpers and sweep the driving lane.. even if it's rough.. a dry swept clay track has mad traction..