How to prevent mould in bath toys

This is the first time in our bath/evening routine that I have introduced bath toys for my son to play with.  He loved the ducks very much - however I am worried that overtime they will get mouldy.

The bath toys we have are the Playgro Bath Squirtees which we received as a gift from one of my friends. It comes with eight bath toys however I have only put two in my son's bath for a couple of reasons:

1. he is only young and I do not want to overwhelm him with too many toys.
2. Should a toy get mouldy I do not want to have to throw a whole bunch out at once I would rather just get rid of two at a time.

I have read a bit on the internet and it turns out the ways to prevent mould include:

• mixing vinegar and water in a bucket and soaking them overnight and rinsing them out with water
• after each use make sure that all the water is out and dry them off and let them properly dry in another room or outside in the sunlight.

Do you have any tips for bath toys? Do you let your children have toys in the bath? If so, what toys?