i used to spray my casing's interior with flat black..
2 time spray. 1st time failed, easily scratched
redo again 2nd time with proper way, i remove the sprayed layer/do sanding/coating with primer coating
still, never succeeded.. only last for hours...
once i placed my hdd, gpu, dvd drive can see scratching already
it is advised not to change place the 5.25/3.5" items once it is placed.
or else the casing interiors will look uglier than the ori conditions bbcoz of scrathes