In the Mishna it describes how to take care of metzios: spreading out clothes, etc.
The Gemara discusses spreading out clothes for both tzorech of the clothes and your own use. Then, the Gemara addresses utensils, saying that wooden utensils need to be used to prevent their rotting.
Then the Gemara describes what kind of use each utensil gets, silver not for hot, etc. The Gemara does not say you must use them to prevent their getting ruined.
1. Does the Gemara mean you may use metal utensils (as opposed to wood which may rot otherwise) for your own good even if they don't need it? If so this contradicts the Mishna.
2. Even if they do need to be used (or for wooden utensils which may rot otherwise) clearly the benefit is both to the finder and to the utensils. Why does the Gemara not use this as a proof earlier when discussing clothes?
Tosfos (30a DH l'Tzorcho) writes that only Kesus, clothes, have the Halachah of "l'Tzorchah v'Lo l'Tzorcho," for we are afraid that he will continue to use it and it is easily ruined. The Halachah does not apply to a book for it has a specific time of use (therefore he can read in it even though that is also l'Tzorcho), and it does not apply to utensils for they cannot be ruined through this type of use.