I have kept the full-size SD-card adaptors for the micr-SD cards, and keep the adaptors in the J.Burrows holder, along with a slip of paper, with the number written on it, and details of what is on the card.
It is easy enough to pull out the slip of paper and write in new details when the card gets changed.
Simple system, I now don't get the cards confused.
It hasn't arrived yet. This is an alternative way to organize the cards. There is a surface to write-on on the back, which apparently is plasticy, so with the appropriate temporary marker pen, I guess the labels could be erased.
For me, it is looking like my first solution is the best. The J.Burrows holder is bulky, but holds up to four Flash sticks, so is a handy thing for when I am traveling, to keep all my memory devices together.