Idioms - "to use elbow grease"

"To use elbow grease" means "to use more strength to clean something" "usar mais força para limpar alguma coisa"

Example:
 That floor has black marks on it. You're going to have to use elbow grease to get it clean.
other example: The bath was so old and stained that we couldn´t get it clean no matter how much elbow grease we used.