Indelible ink is which cannot be erased or washed away. Many countries use indelible ink during elections by marking the finger of the voter to avoid repeat voting fraud.
Image from http://en.wikipedia.org
The ingredients of indelible ink contains water, dyes, silver nitrate and other chemicals.
Silver nitrate is an oxidizing substance classified under Class 5.1 in transport regulations however indelible ink is generally not a dangerous good.
WhatsApp your queries