I am in the final stage of the Witcher 3, and trying to collect all Alchemy recipes and available Diagrams, especially for rare swords.
I cleared most of the question marks in Skellige, except those in water which are always either a Smuggler Cache, or Spoils of War. I just hate fighting tons of sirens, risking losing the ship, wasting ~10 minutes of real time just to clear single location. After two of those, decided to ask first.
So the question is: are there any alchemy recipes or diagrams in Smuggler Caches or Spoils of War locations? If there are, I'll swallow the frog and clear them all as well, but if it's just useless loot I'll pass, I got way more money than I need anyway. (In the game. ;))