Mini offerings can be left in key hiding trinkets. They are discreet and no one will expect offerings in there. They also can easily be hidden in plain sight and in local parks for those folks who don’t have yards or places to make offerings outdoors.
Key hiding boxes can also be used as protection. Hide a key that doesn’t belong to your house to confuse. Place protective items inside to protection. Buy one of cast iron to keep away spirits and the fae.