We often open several cosmetics at the same time, so by the time we realize it, some of them have been expired for some time.
In fact, since the European Union established that any cosmetics with a shelf life of more than 30 months are not required to put the expiration date on the package, we find that many cosmetics do not have an expiration date. The important thing in these cases, and in most cosmetics, is to pay attention to the recommended time of use after opening (RUT).
If we notice any alteration in the color, texture or odor, we must remove it. Perfume in general is lost with time and this is normal, but if there is an evident change in it or a bad odor appears, it would no longer be valid.
In particular, sunscreens tend to destabilize and lose their effectiveness, so in this case it is necessary to be very strict. They must be protected from direct sun exposure and heat. If it expires, changes color or odor, or if its texture changes, it must be removed.
Cosmetics that have been exposed to the sun or nearby sources of heat may contain toxic substances from the container itself that mix with the contents. For this reason it is very important not to expose the containers to the sun or heat.