Castaway Paradise

To donate collectables, you first need to unlock the Northern section of the map (this requires 9 Puzzle pieces) and then you need to open up the Museum. Puzzle pieces can be earned from doing Quests or they can be bought in the store for 2,000 coins. You will need 900 (additional) coins to unlock the Museum. Once it’s open, go inside and speak with Harold. You must be carrying either a Shell, Fish or Bug to donate. After your first donation, the trophy will unlock.

See Hoarder! for a full list of all the collectables available.