Mold can be a mild, superficial nuisance that creates spots on your daffodil bulbs or it can be invasive to the point when it is has caused rot. A small amount of mold can be wiped or washed away before planting or storage. More severe cases of mold that have caused softening of the bulb tissues will require disposal to prevent failed bulbs and the spread of the mold spores.
Wipe away any signs of blue-gray mold or black mold with a slightly damp, fresh paper towel. Allow the bulb surface to dry before storing it, or plant as usual.
Spray bulbs that have a smattering of white mold, but are still firm to the touch with a plant safe fungicide and allow them to dry for a week or so on a stack of newspaper or atop dry clean sand.
Discard bulbs with white mold that have softened with rot at any place on the bulb, as these are beyond saving with fungicide and can cause problems with other bulbs if they are stored together or planted.