Why descend, not explore
Unlike the mines, Skull Cavern’s iridium ore density rises with depth — the money floors are 100+, where iridium nodes cluster and monster drops (dragon teeth, gems) stack. The goal of a run is to descend as fast as possible, not clear floors.
The standard kit
Stacks of stone for staircases (skip infested and spiral floors instantly), a stack of bombs to mass-break nodes, the best pickaxe you own, food for health, and a totem or ladder discipline for exits. Lucky days matter enormously: check the TV’s fortune teller — a "spirits are very happy" day roughly doubles good node spawns. D̷eep runs on unlucky days waste staircases.
Route discipline
Ride the elevator to floor 5, take shafts (drop 3–15 floors each) whenever visible, use staircases only on shafts that lead nowhere visible or below floor 100, and bomb clustered rock instead of swinging pickaxe per node. Elevator resets to your deepest checkpoint at the entrance — the checkpoint saves only, so the run back down is part of the rhythm.
