All it takes is to have a hot shower. It doesn't always work and may be more prevalent in the winter when it's cold in the bathroom but I have repeatedly weighed myself before and after a hot shower and typically lose 1 - 2 pounds.
Your mass doesn't really change from taking a shower. It may even increase due to absorbing water but your weight will generally go down. This is because heat rises causing an updraft around your body, tricking the scale into reducing your weight.
If you track your weight daily, this would be the best time to weigh yourself. :)
Note that if the temperature in the room is close to your body temperature after the hot shower, you may not notice much of a difference but give it a shot and start feeling ten times better everyday!
Other weight-loss workaround tips:
- Always weigh yourself right after you get out of bed in the morning. This seems to be when you weigh the least.
- Go to the bathroom before you weigh yourself. This sometimes helps.
- Don't wear any clothes when weighing yourself.
- Weigh yourself before eating any food.
- Have your hot shower right after you wake up and then weigh yourself.