Replacing Worn-out Elastic in Vintage Clothing

So I decided to brave an attempt at fixing some sleeves on my little vintage dresses. Two had the exact same problem: worn out elastic in the sleeves. Otherwise they are in excellent shape!

So I whipped out my trusty elastic thread and went to work.

(Excuse the bad lighting in the photos...)

After I took out the old elastic, I was left with this:

I sewed around the sleeve following the old sewing marks with some elastic thread and tada! Re-ruffled sleeves.

What a difference, right!?

Here's the other: before...

... and after! Much better.

I also took it around the waist of these pink corduroy overalls, but the effect wasn't quite as great because of how heavy the corduroy is. It worked okay, though. I'm good with how they look now.

I love elastic thread! What's your secret sewing weapon??