I’ve always struggled with cleaning up the squeezeout from gluing miter joints. When I was working on a mitered box recently though, I was struck with an idea. Once I was ready to make the miter cuts, I took some painters tape and laid it on the edges of my workpeices, overhanging where I was going to make the cut. After making the miters on the table saw, I had a perfect “zero-clearance” tape right up to the edge of that board.
To keep the squeezeout off all of your pieces, make sure you do this for all edges that are going to be glued. I did the glueup as normal and clamped everything in place. I came back once the glue had dried and peeled the tape off to find a flawless, glue-free surface left behind.