I use a round pyrex pie plate, any size, and use razor blades like this (Brand is SEB, and I get them at walmart)
I like the round ones better than the square/rectangle, because I can get the oil out of every square inch of a round one, the one continuous corner being much easier than the tight 4 corners of a square dish. The square/rectangle ones may be slightly easier to get around the sides, but only if you are impatient, etc. Even so, the 4 corners are damn impossible, with a standard blade like above.
I get everything out of my dish, using the following method. I hold the blade with a pair of vice grips, like in the pic above, snd I start by scraping anywhere on the flat surface, going in circles, until I get almost all of the oil on the flat surface. Then, I make several passes, from the center, to the outside edges. When I get to the edge, I push a little more firmly, and go up the side of the dish. The razor will bend, just enough to keep a good contact with the glass. Part of the trick, is keeping as flat of an angle as possible, and using small, more "needle nose" like vice grips. This helps you keep from breaking a blade (haven't done that in months)
Once I've gone around the dish completely from center to the edges and up, I go around the dish going down the edges just to get anything I may have missed...or I go around the edge, holding the blade sideways...
I will take a video of my scrape, with my next run. That should be this weekend. I never end up leaving anything usable behind. if anything, it is miniscule compared to what is left behind on a dabber, after a dab, etc.
I think the PTFE and Silicone alternatives to glass are cool, but there is a reason people have been using glass for so long. I'm anxious for my dish to come in the male (glass, worked) so I can be rid of parchment paper, and the rest. I really don't dislike parchment, silicone, or PTFE products; if used correctly, (mainly don't scrape, be careful if you do, and don't abuse the product) they are safe and useful products. I just don't see a lot of benefit to using them. The easiest part of my whole oil making process is the scrape/transfer. Currently, I scrape, then it goes onto parchment. I get it off of one razor, using another, or heat. Once I have my dish, it will just be from the 'rex, to the dish. I was once kind of opposed to dished, and really turned on to parchment paper, because of dust/cat hair/airborne debris. But I've decided that I like the idea of having my oil in glass, for several reasons (looks, ease of dabbing, ease of razing those last few straggler bubbles out with the torch, without degrading your parchment paper, etc)
Sorry for the rant at the end there. I'll try to get that video up soon!