Mechanically damaged aluminium electrolyte capacitor - is it very toxic?
From: Cornell Dubilier

Avoid ingestion, contact with the skin or eyes, and avoid prolonged inhalation.

In the case of electrolyte contact to skin, immediately rinse the exposed area with soap and water. If electrolyte contacts eyes, flush for 10 minutes with running water and seek medical attention. If vapors are present, ventilate the room. Smoke from burning electrolyte is irritating but does not contain dioxins or similar toxic substances. Seek medical attention if any symptoms persist. An SDS (Safety Data Sheet) is available for the electrolyte solvent base material.