I expect this has been covered in prior thread, but I’m new to Glowforge. 
Any suggestion on the best stuff to use to mask/protect materials? I’m using basic masking tape but finding it’s not alway protective and it’s hard to weed it all out of the nooks. Would love to know what others are using.
Most folks use this:
https://www.signwarehouse.com/c/enduramask-mht-130-medium-high-tack-transfer-tape
Gorilla tape is fantastic for removing the masking after a print, along with plastic razor blades.
It will depend on the material you’re working with what “tack” level you want–I prefer the low tack myself when I do have to mask (and it’s easier to remove than higher tack stuff, too). You can always find painters tape and feel the differences between the tack levels that are available. And it’s actually OK to use it for masking, too!
And recommend to get a width that is at least as wide as your project–though you can put on multiple pieces, but do “butt” the joints, don’t overlap them.
So, yes, if you do a search, you’ll find many long discussions about this.
I like TransferRite Ultra 592U High Tack (I bought mine from US Cutter, but you can shop around) for hard materials and the 582U Medium tack for paper. It needs to be burnished down. I find that the Medium Tack barely sticks to wood and tends to curl up on the edges, so I can’t imagine using anything less than that in this brand.
I use a medium tack transfer tape and have also found this. One thing that helps is sanding your material to a finer grit. The finer the finish on the wood the better the hold. Also, beware father time. Just like the proofgrade masking, the bond on this stuff grows stronger with time. I normally use what I mask right away, but I found a board last month that had been sitting masked for awhile and that masking was not going to curl.
Good tips!