When children grow out of a car seat, parents are left to figure out what to do with the unit they are no longer going to have any need of. Consumer Reports has come out with an article focused on this conundrum, and perhaps the most important takeaway for parents is the fact that these products should not be sold or lent out to anyone. Car seats typically have an expiration date about six years after they were produced due to their propensity to lose structural strength over the course of time. Structural issues can be exacerbated when the seat is involved in a crash.
Instead of compromising the safety of someone else’s child, it’s best to recycle the entire unit. Your area could have a program for this, but if not, it may fall on you to take apart the seat. Consumer Reports outlines how to do so at this link.