LOL like Planet Fitness is not even a gymGyms that don't allow chalk aren't gyms they are fitness centers.
Aside from my unwanted opinion, use liquid chalk. As it's been stated here already, chalk will multiply your grip strength big time.
Another excersise is to load up a heavy add bar on a power rack (saftey rails) at a height where you barely have to lift it up off the rails. Grab it, lift it 2 inches, hold it for as long as possible, drop that shit. Repeat.
I tried that sort of exercise as a warmup before I do shrugs or deads and it does help. Worked up to 315lbs so far, and able to hold that weight for 15 seconds.
