Caution: Picric acid can become explosive if allowed to dry out and is toxic through skin exposure. Formaldehyde is a carcinogen. Glacial acetic acid is caustic. Use protective equipement and prepare under hood in a well ventilated area. Reference proper procedures and disposal.

Recipe

1.Stock solution

   3L Saturated picric acid

   1L Formaldehyde

   200ml Glacial acetic acid