The Garbage and Travis stars donated their art to Crafts for a Cause, leaving the American-based charity organisers "blown away" by their efforts.
Edinburgh-born Shirley said she was "amazed" when she found out somebody had bid over $1,000 for a t-shirt she painted on.
And Travis frontman Fran Healy's handiwork with a paintbrush raised $152 for the cause.
The Scottish musicians teamed up with the likes of Neil Young, Kings of Leon, Mark Ronson and Christina Aguilera to raise over 30,000 by auctioning off their hand-made goods. The cash is now on its way to help the survivors of the devastating earthquake in Haiti, which killed over 200,000 people.
Garbage singer Shirley – who recently announced she is back in the studio with her band after a split – donated two t-shirts, with one selling for $1,001.
She said: "To the person who spent an absolute fortune on the two t-shirts I created for the auction, may I simply say that words cannot express how deeply grateful we are to you for your show of generosity.
"You have done something very pure, very wonderful."