Any ways how to minify core JS/CSS files in Magento 1.x? (Prototype.js, etc) Thanks
I used this extension
Worked really well for me.
Best of all - it's free.
Libraries like prototype and jquery are available minified anyway. For other stuff I use Fishpig's Minify... https://fishpig.co.uk/magento/extensions/minify/
It's not free but it works really well and the support is excellent.