This is a short chapter book about 2 girls who find a magic glove in a box of old things. It allows them to draw like an artist and play the piano beautifully.
What the Witch Left (1973) by Ruth Chew
There's a summary on a (fan?) website devoted to her. Here's a relevant bit from the summary:
Katy and Louise find some things locked in a dresser: a bathrobe, gloves, boots, a mirror, and a metal box. The gloves seem to make Katy play the piano, do homework, sew, and draw much better than usual.