hi ladies, im 31 weeks pregnant with my 3rd and...

hi ladies, im 31 weeks pregnant with my 3rd and starting to orgainize the little bits and pieces for bubs...my question is I have been using the same bottle and teat brand for the last 2. after last bubs and storing the newborn teats etc etc away properly and thoroughly cleaning them. Opened the container yesterday and the teats have got a yellow tinge to them :( is there anything that I can clean them with ?? I don't really want to pay for something that I have already got :) thankyou in advance