In some cases refrigerating the ink will make it visible again, but not reliably. Leaving notes in your car can cause then to be erased. So these are a novelty or for casual use.

A fantastic use case though is in sewing. Ironing the fabric makes the ink transparent. These pens are far superior to chalk for that reason.

As long as your clothes are not to be worn in a sub-zero climate.

My understanding is that they are telling me it’ll irreversibly lose color over time. But I have 5 and 10 year old notes that are still fine, so I’m not sure I believe that.

Pilot also updates the formula so a frixion bought today has much better colors than one bought 10 years ago