Just dip them in Lux suds every day. Lux keeps the silk nice and springy, so it doesn't break so easily into runs.

10 seconds sound clip from the The 39 Steps (1937) classic radio play.

You can hear this line at 00:18:43 in the radio play.

Quote context

[...]

- More secrets, Betty? The house is full of them.

- Now the door is closed, we can talk.

- Aunt Sally, what can I give Mother for Christmas?

- Did you ask her, dear?

- Yes, and she just says all she wants from me is love and kisses.

- Well, I did hear her say she needed more stockings. How about getting her some of the lovely sheer ones we saw in the store today?

- But she always says sheer stockings are extravagant.

- Not necessarily, dear. They wear very well if you're careful about washing.

- Just dip them in Lux suds every day. Lux keeps the silk nice and springy, so it doesn't break so easily into runs.

- Then I'll tell you what. I'll buy some and tell Mother I'll Lux them for her, every time she wears them.

- I'll buy a big box of Lux and give it to her with the stockings.

- Now, that's a real Christmas gift, Betty.

- Okay, I'll get some Lux Flakes right away.

- And be sure to use nothing but Lux Flakes, dear.

[...]