I placed receivers/transmiters on computer power supply boxes, Sardine an Tuna can boxes, plastic bottles, wooden boxes but never tested on a toaster or lunch box... If the receiver doesn't work or solar activity is low you can always make a nice toast! Found this while "surfing" for relaxing from my homebrew problems (see the end of this article)...
From OH6DC "Toaster tranceiver" at: http://sites.google.com/site/oh6dccw/toastertransceiver
Now for the lunch box (I really like this one..)
Original article at: http://sites.google.com/site/oh6dccw/picnictransceiver
Give a look at the stange cw keys collection (their really strange)... http://sites.google.com/site/oh6dccw/strangecwkeys
This post was supposed to be on the Si570 but after assembly of the kit (see last post) I saw that it is not working 100%. I am "debugging" with the help of Kees (the kit maker) to find the issue with it, everything looks normal but I am having some reset's addressing some memories. I hope I don't have to send the kit for repair, last one it was my fault (very stupid) and I am sure this one is also too! So I want to spare myself the shame... :)