Swear Jar is a jar of money. This jar is owned by Manny. If Greg or Rodrick says a curse word in front of Manny, they will have to give money to him as punishment.This idea was thought of by Susan. The jar was made so that Greg and Rodrick wouldn't swear (Even though they did it anyway, causing Manny to become rich). Soon, Manny wanted Mom to make up substitutes for different swears that has very low value (Mom Bucks) so they wouldn't go broke.