The whole point of this exercise (if it has a point at all) is not to come up with acronyms with justifiable expansions, but to come up with something that is less newbie-bostile. I'm not sure CLR/CDR fits the bill any better than CAR/CDR. Part of the problem with CAR/CDR is that CAR is an English word that means automobile, and people get a little hung up on that when they first see it. Likewise, CLR is usually a shortened form of the word "clear". So I'm not sure that CLR/CDR is any better than CAR/CDR. One of the advantages of LHS/RHS and FST/RST is that none of those trigrams have any semantic baggage associated with them other than their intended meaning.