OK for this I got an old scanner, and I mean old. Parallel.
Take off the lid, throw it away. If you need to take the hinges off take it apart and remove them.
Then simply get some draught excluder tape. Its about 8mm thick and about 10 wide. ITs cheap as shit, you can get it at any hardware shop.
Its sticky backed, so cut it up and make a frame about 1" from the scanners glass on its top, so that
A the glass seats on it to stop it moving or being scratched.
B it seals in all the light so you dont have patchy bits.
Get some masking tape, as wide as poss.
Lay the glass on, one area at a time. ALWAYS make sure you create overlap as the edges for about an inch are darker than any other part of the scan (but this could be my whack scanner I used to use) I dont think so though I think its because the FM glass doesnt meet the actual scanners glass.
Masking tape it to the scanner, making sure the glass is pressed onto the draught tape firmly. Scan.
Remove masking tape, move, tape, scan.
Crazy fruits was a bloody big top glass, took me about 5 passes with the scanner. A bottom glass however takes 2 or 3.
Of all the scans Ive seen, Liam seems to know exactly what hes doing. So if he can add anything to this it would be appreciated.
His scans literally take me about an hour for both glasses to get back together totally ready to be DXED.