Replace your current dual light switch plate with this one! The paper is from a 1960s vintage sewing pattern instruction booklet. The plate itself is unusual-- made of pale yellow colored plastic, with an extended width, though it will still fit your current dual light switch configuration-- the holes are drilled in the standard spots. It measures 4 1/2 x 5 1/2 inches, and the single toggle switch is on the left half of that.
Screws are not included-- the ones you have in your current light switch plate will translate well. If you would prefer new screws, let me know, and I'll get some 'on the cheap'. LOL
All of my light switch plates and electrical outlet covers are sealed with 4 (or more) layers of matte finish sealant, and are more than capable of surviving typical use. You prolly don't wanna take a bath with them though. Just saying.