I believe you mean a 'water washable temporary solder mask' as used for wave solder processes. A quick search found products made by Qualitek, Tech Spray, Kester, and more. This type of masking has been available for over 25 years, so finding one that does not leave residue, or alternatively finding an additive for your wash cycle should be no problem.
There are also temporay masking materials that are latex based that can be applied and peeled-off. Maybe they leave less residue.