Looking and some ways regular weight training exercises can be adapted to grip strength training for BJJ.
Warm up - Farmers Walk with heavy weights for 5 mins (resting grips when needed).
Mobilisation of hands, wrists, forearms, shoulders and neck.
Dead Hang - 3 sets, until fail.
Inverted Row - 3 sets x 6-10 reps
Bent over/Landmine Rows - 3 sets x 6-10 reps
Deadlifts - 3 sets x 6-10reps
Weights should be heavy and hard to lift by the 6th rep. Always seek advice from a professional if you are new to weight training.