I try really hard not to touch tissue when I prep teeth or when I am delivering bonded ceramic restorations. Blood is the enemy and I don't like red margins. Sometimes though, it just can't be avoided or I get a little rambunctious with the triplex syringe and there is a little bleeder. I have used all kinds of hemostatic agents with mixed success.
My favorite for little bleeders is 35% hydrogen peroxide, the stuff we use for internal bleaching. Be careful with it since it can burn tissue easily and is very bad for eyes and faces. However, if you moisten a tiny cotton pledget and dab the bleeder – POOF! Instant chemical cautery. The bleeding stops. Rinse gently and thoroughly for at least 60 seconds after the bleeding stops because the nascent oxygen that is being released takes a while to complete its reaction. If you don't rinse carefully, you will create micro-bubbles in your impressions. The tissue will turn white for about five minutes and then returns to normal.
Fast, easy and clean!