"If you want to make this a business partnership, Mr. Hart, with all nonsense cut out of it, I'm in on it. I know something about vaudeville teams in general; but this would have to be one in particular. I want you to know that I'm on the stage for what I can cart away from it every pay-day in a little manila envelope with nicotine stains on it, where the cashier has licked the flap. It's kind of a hobby of mine to want to cravenette myself for plenty of rainy days in the future. I want you to know just how I am. I don't know what an all-night restaurant looks like; I drink only weak tea; I never spoke to a man at a stage entrance in my life, and I've got money in five savings banks."

"Cravenette" sounds like the name of a fabric. But what does
she mean by it in this context?

Signals over. I had a hunch and searched for "Cravenette cotton wool" and found this:
"CRAVENETTE. Reg. T.M. of Cravenette Corp. for a water repellent process for fabrics."