Had a good soak yesterday. I picked up some T121 Sweet Caporal WWI Scenes cards and one of them had a glob of some sort of adhesive. I soaked it overnight and the next morning it started flaking off so I left it to soak all day yesterday. When I got home the glob popped off fairly easily. It left a slight stain where the adhesive was but it looks much better than it did. Total soak time was around 24 hours.
Before and after (the after pic was taken with my phone and doesn't look that great... the actual card looks much nicer):
