I would recommend doing it outside as it stinks and the rust from the steel wool will stain concrete so do it in a shop or over the road. DIY Vintage Wood Stain look. (How to age new wood). Good for all things wood!
Jenny: This is interesting envelope package because it's heart shape normally the envelope it's rectangle or square shape . The good thing is the heart shape also can be a rectangle shape. but when you open it . It is a heart.