You can find loot that spawns in other areas with less tedium. At best, you can easily scorch the slime pit if z-levels are turned on. Set a raging fire, climb up to a safe area, and come back after waiting a bit. Once you ash up the entire slime pit, top to bottom, it should stop the spawning of blobs.
Sometimes there are shoggoths in pits… so yeah, watch out for that.