What causes slow drying of gloss and varnish on new paintwork?

With solvent-based paints, it's usually surface contamination as the result of a poorly prepared surface. Water-based paints can be slow to dry in damp, cold conditions, or when applied to timbers that are oily by nature, such as teak. Wet solvent-based paint may be removed using cloths soaked in white spirit. If this is unsuccessful, completely remove the coating using a hot air gun or a suitable chemical-based remover. To remove slow-drying water-based paints, simply wash off with warm water and detergent solution.