"Back in the Day," we used to tie foil pie tins, old tires, milk jugs, you name it on the saddle and let them loose to buck in a pen until they got over it. Most of the ones I saw, being sensible, decided it was a waste of energy after less than 10 minutes.
However, I wouldn't do that today. There are quieter methods and I am a great, huge fan of the Patience Tree. As in tied to, until you learn "chill." No matter what's tied to your saddle. We did some old-timer "cowboy" things in the old days, and got away with it, but we were also doing it on a lot of $200 school-horse candidates fresh in from the sale.
If you've got an inveterate bucker or spooker, however, and a pen he can't run through . . . some of the real knotheads still need it.