The car was filthy when he returned it to me, and 'to cap it off' [='to top it off'], there was almost no fuel left in the tank.
a 'shower/bathing cap' [=a head covering that people wear to keep their hair dry when they are showering/swimming]
They may not like being called careless, but 'if the cap fits, wear it'. [=('US') 'if the shoe fits, wear it']
(..) You get in front of it and put it in the damage path. And then get out again quickly. That's the suck zone. Excellent! We got major action! N.S.S.L. says the cap is breaking, towers are going up miles. Let's go. We're moving! It's fatty time! Laptop. (..)1996 Twister