Deposits to an HSA after going on Medicare

I retired a few years ago and turned 65 last year. I have had an HSA for several years. I know that once I turned 65 I can’t make a deposit and claim it on my taxes, but can I make a deposit anyways, since the money will have already been taxed. I’d like to keep my HSA as a savings account for medical in the future…

There is a bill to change the law but at present you can’t do this.