not used too long and wasn't kept in perfect condition.
Not too many rust, but some brown spot seen,
can I still use them after good clean with water?
Would any tiny metal pieces get into the food?
Sure. Rust is ugly but doesn't affect blade performance. I assume you are using carbon steel blades like I do. Shake some Bar Keeper's Friend on the blade and clean the rust with a Dobie or sponge. If you have carbon steel blades you should allow the knives to develop a patina. Then they will stop rusting.not used too long and wasn't kept in perfect condition.
Not too many rust, but some brown spot seen,
can I still use them after good clean with water?
Would any tiny metal pieces get into the food?