My white bikkini has gone yellow?

Went on holiday had a lovely white bikini, problem with the sun, sun cream, sea and pool and sweat yeah sorry but u no hot sun n all is now a mucky looking yellow, is there anything to get it back white or shall ibin it, it cost £30, so wasnt cheep.
Answer
Try steeping it overnight in a basin of water with a few denture cleaning tablets in it and then wash as normal. kim and aggie did that with discoloured bras and it worked a treat.