Brush for cleaning Nozzle with the Start G-Code

My way to clean the Nozzle before each print For the CR10 printers and all like

Here is my story...

The printer came with a concave glass like many of you and of course the solution is to replace it.
So I went to the local mirror store and asked the man to cut a piece 300X300 mm like what is known about the dimensions of the printer
He suggested to chamfer the edges for safety and I agreed
When I returned home I put the mirror on the heated bed plate
I found that it came short and aft