I usually try to roast towards the bottom of my garden so as not to annoy my neighbours too much and carry the gear down in a couple of cardboard boxes. I use an old set of Salter scales for weighing and on this occasion, when I got back to the kitchen I found that the 5g brass weight was missing. After checking the 40yd walk (mostly across grass) several times, I didn't find it – the lawnmower didn’t find it either and I haven’t got a metal detector.
After a bit of lateral thinking, I came across this site:
http://www.24carat.co.uk/coinspecs2000.html and found that a 20p coin is exactly 5g – bit of luck eh?
The other coin weights could be useful for calibrating your scales.
Cheers
Ian