A small webbing patch that they use on cars and to patch drywall holes is cheap and effective,,you can buy a small roll at walmart,autozone or home depo,lowes,,,,you have to have something like the webbing to smear mud[filler] on,,,,, the webbing{looks like a roll of screen,,] is tacking and very thin,, ,cut your patch,,put in over the hole,,or if you can get your hand inside,,but it really doesnt matter,,,,ive down walls and when I was done ,,,you couldnt see the patch,,,,then smear your mud,,let it cure,,,when apllying the compound use a small thin piece of flexable plastic,,,milk jug or cut out the side of a empty qt oil jug,,they work well,,,what ever you have,,use that to smear your compound filler,,,,let it harden [ cure] then sand it down ,,,if you get it close,,,make sure to use fine sandpaper,,,,
