Silver Nitrate
Pure silver nitrate is caustic in the sense that it will "burn" and destroy soft tissue, such as mucous membrane and "kill' warts. It will stain skin in contact with it (e.g. fingers). It should be kept well away from children.
Doubtless, it could scar the cornea in solid form.
An "older" medical GP used it (on me) very successfully to cauterize small (but painful) mouth ulcers. I have not seen this treatment before or since, however the results were instantaneous and highly successful, needing only a single aplication. (He used bamboo skewer-like aplicators impregnated with the silver nitrate (at the tips) and lightly appply them briefly to the ulcer. Goodness only knows where he got them from as, after he had retired, and when I needed some more of the same, none of the younger doctors had even heard of the technique and the pharmacist was unable to source the aplicators.