If it says to search "Storage Containers" its usually referring to Barrels, and/or Crates. It would also tell you where they would be located.
If your searching for more than one item, then usually one would be in Barrels, the other in Crates. If you approach several crates and are told "Nothing Interesting Here" then it is likely you need Barrels instead of Crates (and vica versa).
Here is a link to the DOW Wiki with more information:
Doll Making Quest