This guy is why you can't get a job
My first advice to interview candidates is to be honest about your own limits. When I am interviewing candidates there is nothing that puts me off more than a candidate with too high thoughts about themselves.
One variation of that is listing too many skills on the CV. When I have interviewed candidates I have often picked out some relevant skill from their CV and asked questions about it. Every now and then a candidate has no clue whatsoever about it and might even be offended that I chose to ask about it.
If you put a list of skills on your CV, don't include one that you don't want to be asked about during an interview. If one of your skills has been getting a bit rusty, you should probably remove it from your current list of skills, but you can still keep any references to it in your employment history as that will also make it clear how long ago it was that you worked with it.