Reduce App is a nice, light-weight app that allows you to compress Sketch files in OS X. The app is very simple: you install it and you drag-and-drop the Sketch file you like to optimize. Then you have the option to select the optimization steps: optimize image size, remove broken images, delete hidden layers and delete unused symbols. You can select any of these optimizations or all.
This elegant tool can save you a lot of time, and disk space and it’s totally free.Download app