Humidification Device Won't Stay On...

[KenyanSandBoa]

Ok...I'm getting tired of having to keep reapplying one of the humidification devices on my humi. The sticky magnets will NOT stay on.

I've tried pressing them on as hard as I could without risking cracking the top of the cover. I was thinking about roughing up the cedar by where the magnets attach and roughing up the sticky pad so there would be some texture for the magnets to adhere.

I figured an adhesive would be a bit risky, but does anyone have any ideas to adhere these things for the long term?

I attached a pic of the humi open so the underside of the cover is showing so everyone can see what part I'm talking about.