The mix I use is 4 parts water, 2 parts Glycerine (which you can get from the supermarket) and 1 part Methylated Spirits. This is placed in a plastic spray bottle for ease of use.
2
Spray each side of the veneer until the mix penetrates the veneer.
3
Once the softener has been applied the veneer is then pressed between sheets of absorbent paper towels and sandwiched between two pieces of Melamine. I prefer to use Melamine as there is no chance of leaching of colour as there would be from MDF or other compressed board.
4
Place a weight on the Melamine to keep the veneer flat.
5
Change the paper towel over a couple of times in the first hour then every few hours for the first 12 hours. It is usually dry within 24hours.