Reusing bottles

renogaw

We threw out our older daughter's 4 oz bottles when she was a baby because they had BPA.  We bought 9oz Born Free bottles for her to use because they were one of the few brands without BPA and I didn't want to buy two sets of bottles ($$).  We're using brand new 4oz Avent bottles right now for the baby.  Is there any reason not to use our existing set of Born Free bottles once DD #2 starts taking more than 4 oz at a time?  I threw out all the old nipples years ago and I'm planning to buy new nipples to use for the baby.  I'm thinking it should be fine, but figured I'd get some second opinions.  Thanks!