2 adverbs to describe how to corrode

A.Marine boilers are corroded externally in the region of the steam chest by the dripping of water from the deck; the bottom of the boiler is corroded by the action of the bilge water, and the ash pits by the practice of quenching the ashes with, salt water.

Joe made careful inquiries of one of the friends he had made among the road kids, and this boy told him that oftentimes these inhuman monsters continued the lye treatment for such a length of time and so fearfully corroded their helpless victim's limbs, that blood-poisoning set in and made amputations necessary to save their lives.

2 adverbs to describe how to  corrode  - Adverbs for  corrode