Years ago I bought a big 3x4 ft. framed picture quite cheaply. I have people think it is a real oil painting until I correct them & they still have to go to touch it & see for themselves! The frame is probably worth more than the picture but I love it anyway but now need to somehow clean it.. Any ideas? I know most things will just remove the color on the paper & am afraid to try anything for fear I will damage the paper it is on & ruin the picture! Would really appreciate any ideas!