The thread says,
Containers may be safe for one of two reasons. Some container types are set to be non-respawning — containers of that type will never respawn, no matter where the container is found. Other containers are safe because of their location — some locations, in particular the player's http://www.uesp.net/wiki/Skyrim:Houses, are identified as non-respawning locations. All containers in these safe locations (even common Barrels and Sacks) can safely be used for storage.
May be safe, not are safe, but may be safe. Only if they are non-respawning.
And yes, UESP is the place to go for info. Just trying to help.
There is one non-respawning cupboard and one large sack that is non-respawning that you can use for storage. Plus entering the house is considered trespassing, and anything you take is considered stolen.
http://www.uesp.net/wiki/Skyrim:Drelas%27_Cottage