The plastic bikini clasps tend to break when they are in the washing machine.  Instead of putting them into the machine loose with all your other clothes, buy or make yourself a bra bag/laundry bag and put the bikini top into the bag to protect it.

If you are going to make your own, buy some of the single fabric with small holes in it.  Cut out a square x 2 and join together at the bottom and sides.  Sew a zip in the top.  You can use this for all your delicates, and especially bras.

Happy sewing

Judith aka genie