I caught this item among the various vintage ads Found in Mom’s Basement, and I pass it on to you:
The late Allan Sherman reworked “Chim Chim Cher-ee” into a satire on American advertising, and referenced the product this way:
“What does that blue magic whitener do?
Does it make blue things white, or make white things blue?”
Your mom knew the answer to that, of course.
Many years later, a band called Blue Cheer would come down with the Summertime Blues.