The itemfinder only works when there is a secret item around the surrounding area try using it where snorlax used to be after you woke it up and caught it/defeated it you will find an item called leftovers.
use the itemfinder and you will eventually find a lot
go to Pokemon tower on the 6th floor use the itemfinder
Use the itemfinder at the spot where mr fuji once stood at the top of Pokemon tower you should dig up a soothe bell. where mr fuji was standing use your itemfinder there
none. use the itemfinder in multiple locations in berry forest to find berries.
go to bills secret garden. use hella max repels trust me this worked. spin in a circle 360 times around the back bottom right corner of the garden. this will only work if you have the itemfinder. then once you spin 360 times use the itemfinder and there you go a mewtrance on Pokemon leafgreen
You can get the Item finder from Professor Oaks in Pokemon LeafGreen. Professor Oaks is found on route 11 just out side of Vermillion City.
Go to professor oak, Talk to him, he will give you the "super itemfinder" use it when using the map
Nuggets can be found in caves or even hidden around the ground using the itemfinder.
Just find the itemfinder press A and select 'use' then you're using it!
Moon stone is found in 4 places: One is hidden in Mt moon use the itemfinder to help you, another is also in Mt moon, one is given by the man who owns the two island game corner, the last is found in Pokemon mansion use the itemfinder to help you.
Once you have the itemfinder and pokeflute go to the top of Pokemon Tower which is in Lavendar Town, once your at the top stand in the spot where Mr Fuji used to be and use the itemfinder if your in the right spot you should dig up a Soothe Bell item.
use the itemfinder