I didn't like having my glass beds laying around the table so I made this. Print four of these holders along with any number of square supports you like. I print one and then I place it on the center. I've been using this for my 300x300 mm beds, and they stay neatly organized and secure.

I often use a single skirt loop just to make sure I'm getting a clean first layer, but it's not necessary. If you wish to donate, you can do it via paypal here > https://www.paypal.com/paypalme/t4ntric. Enjoy :)