What did Mr. Otis offer to the ghost? Why?

The second night that Mr.Otis spends in the Canterville Chase, his sleep is disturbed by sounds of clanking metal in the corridor outside his bedroom . On checking, he finds out that it is the ghost .

He offers the ghost lubrication for his rusted chains. He claims that "Tammany Rising Sun Lubricator", which he is offering , is very effective .He also tells the ghost to ask for more if required . With this, he goes to bed , shutting the door in the ghost's face. The ghost feels insulted .Then the twins assault him and he is forced to flee to his secret chamber .