Tricking your scale to weigh more.

I recall someone trying to weigh more than their digital scale would allow. Mine only weighs 11 pounds but I have tricked it to weigh 21 pounds when needed. It's a little inconvenient but does work on many scales and doesn't impact accuracy (too much). 

Most scales show a negative when something is removed and will also show zero when the scale is turned on with weight present. If yours does then this may work for you too.

Step 1: Weigh a container of something (water?) to equal 10 pounds.

2: Turn your scale off and then back on with the calibrated container still on the scale. When your scale turns back on it should be showing zero. When you remove your weight you effectively have a scale calibrated at -10lb.

3: Weigh you desired object greater than 10 pounds. Add 10 pounds to your reading and you have a weight pretty close to the accuracy of your scale.

Because of the method digital scales use to measure weight you can typically only go negative slightly less than your maximum weight.

I've used this numerous times to weigh packages for shipping.