Most flea market purchases need a little attention before they are ready to use or display. The goal is to clean them without damaging them, and the safest approach is to start gentle and escalate only if you need to.
For glass and ceramics, warm water and mild dish soap are usually enough. Avoid the dishwasher for older pieces, since high heat and harsh detergent can fade decoration and cause cracks. Dry them with a soft cloth and be careful with gold trim, which can wear away with scrubbing.
For wood furniture, begin with a soft cloth and a small amount of mild soap diluted in water, then wipe dry. Resist the urge to sand or strip a piece right away, because original finishes can add to the value and character. If a piece smells musty, airing it out in a dry, shaded place often helps more than any product.
For textiles such as quilts, linens, and clothing, check for stains, moth damage, and odors before washing. Gentle hand washing in cool water is the safest default for older fabrics, and delicate or very old pieces may be best left to a professional cleaner.
For metal items, test any cleaner on a small hidden spot first. Silver tarnish can be removed with a polish made for silver, but aggressive polishing can wear down detail, and some collectors prefer to leave a light patina in place.
Wash your hands after handling anything dusty or dirty, and inspect used items for pests before bringing them into your home. A little caution at the start saves trouble later.