That is outdated in our archdiocese, anyway. It is allowed for a EMHC to consume the Precious Blood in a solemn fashion, if any is remaining at the end, presumably because the combination of what remains in several communion cups may be too much of the accidents of wine for the priest to take care of himself. This is done before the cup is returned to be purified.
Other than that, EMsHC return the vessels to the altar (in the case of vessels containing hosts that the priest or deacon must transfer over the corporal to the main ciborium that he will then return to the tabernacle) or to the credence table, but purification of the vessels is done by the priests or deacons only, in silence and during Mass. This change was reiterated several times and in no uncertain terms during training of EMHC. Laypeople do clean linens and sacred vessels, but only after those have been ritually purified, and even that is to be done in a solemn manner as well, even the ironing done at home. This was also communicated in no uncertain terms, if in a nice way for all of that.
I know of parishes that have not yet replaced their glass communion cups, though. As far as I know, there isn’t a deadline by which parishes have to spend the money to get ones that meet the requirements, but I’m not in a parish office where I’d be given that information.
The question is whether it is a forbidden that they be returned to secular use. That is, if they are removed from the sacristy, can they ever be used for a secular purpose, or must they be kept out of use entirely? If not, is it required that they be destroyed…for instance, in the case of a glass that has sentimental value? Is it required that the glass be buried, and if so, does it matter where?
If your sister has a priest friend over for Mass at her house, and she uses one the crystal glasses she inherited from Grandma for a chalice, then returns it to the cupboard to mix in with the others, you aren’t saying that the whole lot needs to be destroyed? Or if your cousin does the same so the chalice used at her wedding will be “sentimental” or a priest has a glass chalice he got for ordianation, you’re not saying it must be broken? Or are you just saying that breaking and burying is the way to dispose of glass chalices, when it is necessary, prudent, or desirable to do so? (Does it matter which: necessary, prudent, desirable? Which applies when?)
I’m not trying to be argumentative, just find out what is required vs. what is permitted. If you were to post something definitive on the rules concerning possession and disposal of licit and illicit altar vessels after their use at a valid Mass (licit vs. illicit, if it matters), that would be great.