After wiping down any dirty woodwork with a household cleaner, sand the trim, doors, and windows with 120-grit silicon-carbide sandpaper. Sand old paint so new paint can adhere. Sand bare wood to remove raised grain, level off wood filler, and ease over sharp edges.
When sanding flat surfaces, hold the sandpaper in your hand to get into any slight depressions that a rigid sanding block would miss.
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