How do you avoid getting/get rid of black marks left on walls by picture frames?
I am not sure what they are from, because they also appear for frames that are not black in colour (we have a couple of gold coloured frames), so it can't be paint from the frame transferring onto the wall (also, the back of the frame is intact, without any damage or loss of paint/colour). We really don't know what the marks could be from. Dust? But it doesnt wash off, as one would imagine with dust.
They come with only long term (a few months) of hanging a painting in the same spot. We are afraid to hang any frames in our current apartment because we dont want to leave marks and then not be able to move frames around. I thought of lining the bottom of the frames with sponge-sheets or bubble wrap, but I am not sure if this will protect the walls from the marks.
Any suggestions will help!