Precious metals swung between gains and losses on Tuesday session after falling yesterday as a government report showed that China's exports tumbled by 18.1% last month raising concerns over demand for the metals. Silver for delivery in March added 0.5% to $20.9299 an ounce after falling by 0.6% yesterday, while palladium traded at $775.40 an ounce and platinum slipped to $1,477.13.