Here is some card stock that I aged today using inexpensive, instant coffee crystals. Sometimes, I add cocoa powder and vanilla extract to impart a yummy scent to the paper.
I sprayed a portion of the paper with DecoArt Media Mister in turquoise. The color result was a lovely blue that doesn't show up in this photograph. The card stock is a 110# weight which makes for a more sturdy substrate.
I let the paper soak for a couple of hours and then I usually let it completely dry overnight.
Eventually, I use the aged paper for collage and mixed media art projects.