I agree. Pencil-on-plastic lasts longer than anything else. And you can erase and re-use them! Free to start with, and re-usable! The Price Is Right!
My handwriting is so terrible that I appreciate the fine line of a pencil as opposed to the wide smear of a Sharpie. I can print several lines of text on a mini-blind, even if I cut it in half first.
Sometimes I even cut a mini-blind slat into thirds lengthwise, so I can label single cells in a 128-cell plug tray. Not often - thirds are very skinny.
In fact, even a wooden pencil has a wider line than I like, so I use a mechanical pencil - it's always sharp. I have some "HB" lead, which is very slightly softer and maybe slightly blacker. I usually use a 0.7 mm mechanical pencil, though the finer 0.5 mm works too.
When I remember, I even mark the date I sowed, or the date I transplanted something.
Next time I see a custom blind shop, I'm going to ask for a bucketfull of their cut ends.
One thing that I think is overkill, though I do it anyway: I clean the slats with abrasive cleanser like Comet or Bon-Ami. I imagine that it gives them a slightly rougher surface, to take the pencil lead better. Silly! But clean.
However, don't make this mistake: washing mini-blind slats in a dishwasher can make them curl or bend permanently if the water is too hot or you enable the "heated drying" feature. Maybe that was because I wound them through the prongs in the rack to get more in and keep them from being thrown around by the spray, but never again!
