Water is definitely not a good idea in the long term since that actually helps the remaining microscopic mold to grow.
You want to use a mixture of peroxide water (0.03% peroxide) and isopropyl alcohol (>70%) in approximately equal quantities.
The alcohol will kill the active mold but is unable to kill the spores by itself, only the peroxide water can do that which is why you want to mix them.
I had to throw about half a dozen originals because of that and it is really hard to get rid of if you do not fully swap disks to a new non-infected enclosure so do not skimp and just assume that a simple cleaning session is enough. The old soft inner lining of disks cannot be safely reused as it is full of mold spores.
Also once the alcohol + peroxide mix has dried on the naked disk, you can use a hair dryer at very low temperature to dry it and ensure that no water remains on its surface. Any remaining water even if invisible to the naked eye will be used by mold to grow again.