Other than further tightening the frames at the ears, is there a way to keep plastic frames on one's nose? Do they happen to make any type of material to apply to the nose to give it more grip?

i really like the zyl frames i have. they definitely start slipping after awhile, especially on hot days after a little perspiring. I've had them adjusted to be a little tighter, and i really don't want it to get much tighter at the ears.

thanks for any advice! :)