It only cost me 24p (UK) per antenna for this project, so it is nice and cheap.
My router is a Tenda model, which already has 2 aerials and a dish and only cost me £25, so I would really recommend it.
Step 1: Materials
A Wire Skimmer (for taking food out of pans)
Spare Aerial or stick the same diameter as your aerial
Any other metal strainer/sieve should work to :)