Cob webs, for me, are a part of shop life. Every few months I hit the place with the long air wand and/or leaf blower to help clear them out, but the spiders are still there (somewhere)...lol
The fewer bugs you have, the fewer spiders you'll have, hence fewer cob webs. Keep your rec area bombed and the outside sprayed and even if the pesticides are not that effective on the spiders, the spiders will have less to make a living with, so to speak.
I actually have an appreciation for my spiders in my shop (maybe not the brown recluses in the loft) because they are there due to the bug population in my shop and certainly keep the flying insect population cut back. I'll take the spiders in the corners over that blasted horsefly buzzing my face under the truck with both hands busy, sweat in my eyes, a kink in my neck, and so on.