If you complete the C.O.O twice u will get another bottle of fairy tears. Beware floor 39 and 49 are harder...

Floor 39-This will have 3 armoured knights with 1 under the ledge
Floor 49-This will have 4 armoured knights with 1 under the ledge

If you drop around 3 bombs down you will probably take the armour off the 1 under the ledge then jump down staying as close to the wall as u can u can finish him off.(same for floor 39 and 49)