If The padlock on the back gate has rusted shut.
Then Replace it with a weather-rated padlock.
A shrouded shackle and a drainage-friendly body cope with rain and salt far better than an indoor lock left outside.

Locks for shops, offices and buildings: rekeying at turnover, commercial-grade hardware, exit devices, master key systems and access control.
Running a business means knowing who can get in when you are not there. The commercial services are different ways of answering that: rekey to reset it, master key to organise it, access control to log it, and a safe to protect what matters most inside.
Commercial RekeyingA key turned up in the parking lot with the shop's name on its fob.
Master Key System DesignA new hire at the shop gets handed whatever spare key happens to be in the drawer, and it turns out to open the stockroom, the…
Access Control InstallationThe team has grown past the point where one shared key still makes sense.
Panic & Exit HardwareThe crossbar on the loading-dock door barely returns anymore.
Commercial-Grade Lock ReplacementAn inspection report flagged the rear exit as needing hardware that opens with one motion and no key, and that door currently has…Tap a situation. The answer opens here.
If The padlock on the back gate has rusted shut.
Then Replace it with a weather-rated padlock.
A shrouded shackle and a drainage-friendly body cope with rain and salt far better than an indoor lock left outside.
If The shed holds the bikes and the lock is a flimsy one.
Then A hasp and a proper padlock.
The hasp matters as much as the lock; fitted with carriage bolts it resists prying.
If The mailbox key is lost and the mail is piling up.
Then Replace the mailbox lock and cut new keys.
With proof the box is yours, the cam lock swaps out cleanly and you get two keys for it. Mailbox Lock Replacement
On-site assessment preferred · (289) 206-1975, open 24/7