I use a bag of steel shot to train my iron palm.
I have other various sized bags to train my claws, by grabbing bags I toss up as well as play catch with a partner.
I also train my grip strength as your hands will love you for it.
I use COC(Captains of Crush) grippers as well as plate loading grip machine to blast my lower arms.
I still train my iron palm, though I seem to gravitate toward more qi gong like Royal Dragon, maybe thats a natural progression.
Dale
Mouth Boxers have not the testicular nor the spinal fortitude to be known.
Hence they hide rather than be known as adults.