Alfie:
I think it is great that you developed this effect on your own. It shows you are thinking about how to use the slights you know to do something that amazes your spectators. It also shows that you have also learned one of the most essential lessons of magic -- the slights behind an effect don't need to be difficult for the effect to be amazing. I like the use of the blank face card.
That being said, the card to pocket / wallet / shoe has been frequently done in various forms, including handlings that can be done with a signed card. A book that has a lot of those types effects would be Hugard and Braue's Expert Card Technique.
Based on the fact that there are a lot other handlings of the same effect out there and the fact that your method will be apparent to most experienced magicians (the downside of it being easy to perform), it probably doesn't make sense to "release it."
However, the ability to "release" an effect isn't important... its the reactions. So keep performing it and keep getting great reactions.