Fake Cement Rocks - A la Geocaching

I've tried a lot of stuff to make fake rocks to hide my geocaches. I just had one go missing after about 3 years and it was made of Bondo (and showing it's age) so the last few times I've gone with instant mix concrete.

1. First I take the container (in this case, some locking tupperware), I chuck it in a plastic bag stuffed with newspaper along the sides to take up space so it will have room to fit.
2. Then I take chicken wire and mold it into a basket, a skeleton for the concrete to grab onto and form the shape of the rock
3. Then I mix concrete, sometimes add some pigment for color, and I just slop it on as the wire cage sits on newspaper. I'll edge the sides with stuff sometimes if the concrete is runny.
4. Then I'll take a plastic bag and lay it over the wet concrete and ruffle it a bit to give it a smooth texture with some wrinkles. It also gives you air bubbles and other interesting effects.
5. Let it dry, pull the plastic off and voila, fake rock. Chuck a plastic container under it and go hide it somewhere

Sometimes the natural color of the concrete looks good, other times it's a bit too light. For this rock, I'm going to bury it in grass clippings to give it that moss-green tinge found on the rocks in the area where I'm gonna stuff it. Here is a shot of the waterfall where it's going to go.