We're back with the RA-Tech Howto Video Series. Previously they uploaded a video on howto clean your inner barrels properly and for this new episode it's about cleaning your upper receiver especially for gas blowback rifles as dirt will affect the performance as compared to AEGs where the gearbox will have to be opened up and maintaned properly. Photo above shows the dirt that can stick to your upper receiver so better be aware of it.

Same video was also sent in by Airsoft Taiwan.