Marlowe from North York, Ontario has painted her doors, door knobs, and latches so well that nothing works any more -- the doors just won't stay shut.
It is usually best to remove all the hardware before painting, or at least mask it -- but in this case she wanted to change the colour of the hardware itself. So, how to get it working again?
The latch, that tongue that goes in and out of the door frame, can be scraped clean -- or taken off and soaked in paint thinner for oil paint or acetone for latex paint to soften it up.
If the knob doesn't want to turn because of paint in the joint between the moving part and the stationary part, you could try either dental floss (it gets into small cracks and is very strong), or the edge of emery cloth (wet/dry sandpaper). Emery cloth is rigid, thin, and scrapes paint well -- right inside that crack.