Ever take elmers glue and write on the FP. When burnt, the message appears. One note, for closed loop letters like O,P,A you need to leave a gap to allow the burn to remove the center of the letters.

This can be done for just about anything. Write 52 FP cards and index them in a wallet. Use a thought transmiter to capture the card and burn the right index. With the right patter this is really spookey!!

I like to do Flashburn 2! Its an effect by Simon Lovell that's in his book "Simon Says".
You have a card signed and lost in the deck. You then wrap a coin in flash paper and set it on the deck and light it. It goes up in flames and the coin remains there. It looks as though the trick has failed but under the coin a small scrap of paper remains and it says look in the deck. when you spread the cards out there is one that is burnt so bad that one corner is even missing. you turn the card over and it's their signed card. It really wows them and they get a cool give away. I have had people come up to me months later and pull out that burnt mutilated card from their wallet or purse and say "See I still have it". Its really a killer trick and so easy to do. No slight of hand. If you can hold a deck of cards you can do this trick. You could even do this with a borrowed deck if they have the right kind of cards. And most people do. that's about all I can say with out tipping the secret. But do yourself a favor and go out and get Simons book. Its got over 50 effects and most of them are killer.