What you will need:
Cardboard or paper
Crayons in a range of colours
To give the kids some inspiration and to show them what to do, I created a tree with my crayon rubbing. Then it was over to them, so I handed the bottle of glue to my son and let him come up with his patterns.
You could use a hot glue gun that I have seen in similar kids activities; my kids are a bit too young to use the hot glue gun. They were both happy just to squeeze the bottle of glue and make crazy patterns.
Once you have made your patterns on the cardboard, allow the glue to dry completely. This took overnight, so this is not a project you can do if you need an activity that can be set up quickly. You can make it a weekend/two day long project, with the set up on day one, and the final creation on day two.
The next step is to get the kids to place paper over the top of glue pattern and rub over the paper with a crayon.
Overall the kids love this activity but were a little impatient having to wait for the glue to dry. So if you want to do some crayon scratching artwork and don’t want the use the glue method I have a similar project that can work just as well; try leaf rubbing or send the kids to look for objects that have interesting textures.