If you are eligible this year, reduce your current contributions. You can "use up" the excess by applying it to this year's limit as long as your current contributions plus the excess is less or equal to your current year limit.
If you are no longer eligible, and plan not to be eligible in the future, but you will spend the account down to zero in less than 5 years, then leave it alone, the tax and penalty for removing it will be more than the penalty for leaving it in.
If you are no longer eligible, and plan not to be eligible in the future, but you will not spend the account to zero in 5 years or less, then you can withdraw the excess amount, and not use it for medical care. It will be subject to income tax plus a 20% penalty in the year you remove it, but then there won't be an excess going forward.
