Reading the post about playdoh started me thinking about all the things we used to do and make, like playdoh for the kids.
But what really has me reminiscing is the old mimeograph copies. Somewhere I still have a recipe to make a pan of jelly stuff that will hold ink long enough to press multiple sheets against it so you can have copies of whatever. Now, with computers/printers and photocopiers, putting the time and effort into that would be ridiculous.

What other arts have been lost to technology?

Calligraphy comes to mind.

I think hand embroidery is fast becoming a lost art. An inexpensive machine can do embroidery. No more blackboards in schools, it's all dry erase boards now. No more cleaning the chalk erasers outside! I use to think that was so much fun.

Just plain paper and pencil for school.

Penmanship education.
I did my Master's Thesis on the connection between brain development, literacy, and penmanship education.

Typing paper - bet you can't find it anymore.

Also, we used to buy really thin tissue paper to write on - for airmail letters - they cost more than regular letters.

Can't find carbon paper anywhere either. There is also the lost art of shoelace tying, knot tying and even tie tying. What about the lost art of writing thank you notes/cards....the lost art of mending (especially sock darning) and the complete inability of people when it comes to polishing shoes!

The art of letter writing. And I'm guilty of it. Used to love to write letters to loved ones. Maybe I'll do it again!! :D

Counting change out? If the register doesn't tell them how much to give you in change, they're lost!
I love the look on someones face when I let them ring up my money, then throw them a few pennies. Sometimes I'll say "here's 3 pennies, just give me a quarter back". lol

I took a calligraphy class in high school and kept at it... I used it to send out the invitations to my wedding. Everyone remarked upon it. Sad, but I do think with the technology we've got, this is truly a soon to be lost art. Why spend all the time and effort when a computer "font" is so easy and perfect?