Do you like cotton jersey pillowcases? I purchased a set of cotton jersey sheets ~20 years ago. The pillowcases wore out first, because I like the softness next to my face. The jersey sheets, OTOH, took so darn long to dry that I didn't think they were worth the energy premium over other sheets.
Moreover, at ~900 gallons per XL cotton t-shirt, it's an excellent way to mine water. If the thrift store is in your neighborhood, you are even mining water transported to your local watershed!
I trimmed the sleeves and top part off to make rectangular shapes, preserving the hem. I then augmented the length with rectangles of denim that I purchased online but weren't suitable for the project I had in mind for it.
In about 90 minutes, I had 6 pillowcases. The backsides of all these Ts are plain and soft against the face. I left the motifs on the outside because I find them amusing. If the motifs bother you, just use the t-shirts inside out. If the inside-out hems bother you, sew the denim or other fabric rectangles on the hem/opening side.
I found a blouse-weight soft 100% cotton dark indigo denim in the remnant bin at Joann's ca. 2009 and used to make ruffle skirt #1.
unvented this style of skirt because 2/3 of a yard of fabric (even if it is 60" wide) is not sufficient for four tiers of ruffles.
I liked the fabric so much, I went back to buy more only to discover that the dark indigo color had been discontinued.
I found a light-weight denim from Robert Kaufman at Fabric.com, but it was too heavy and stiff for the t-shirt I wanted to make.
denim ruffle skirt #2.
I'm glad that the mail-order denim found a good use.