Clean your tires. On dirt tires, the dirt soaks up the oils drying up the tire.
I have never been fond of heavy saucing a rubber tire, but I do coat the tire with a drop or two of something 15min before I drive. I used to just dab some DeathGrip on the tire and use my tire towel to rub it around the tire. Now I just use Jack the Gripper. My goal is to have clean tire the grabs the asphalt heating the tire up to temp faster than a tire that slips becuase of excess solvents weaping out.
All my tires foam or rubber are stored in air-tight containers to extend life. Ozone and air will affect a tire big time and make then harder and slicker. Saucing your tire and storing them to me is a Big-NO-NO. The solvents continue to break down the tire and glue bonds while the VOC are gassing out. Best to store your tires wiped and dry.
I have some Take-Offs that I thought were good tires (4 years old) and I just ran some new tires and I was amazed at the difference old vs. new tires. I didn't buy my tire containers till last year, so my tires had 2~3 years to dry out in my garage.