You didn't say the weight or what they were attached to so it's hard to say if this will work but, maybe double faced tape

One of them was attached to one of those stick on plastic lights and to the bottom of the cabinet. I've got Elmer's on it now but I haven't tried to twist it to change out the batteries. That will be the test.

The other one was a command strip stuck to a picture frame. I used Elmer's on it too and it will probably hold fine because once it's in place, it won't be touched again.