You must kill 10 people with a explosive gun like AC or a petrol bomb then you will get like 5-10 napalm grenades.
The blue effect makes you heal faster when you have a heal staff and the red one used to give a damage boost for the explosives but it doesn't seem to do that anymore and the yellow one you get from killing 3-5 players fast not sure what u get from it though.
I believe you turn red when you get 5 very quick kills with an weapon that doesn't have standard bullets (I think the flame is an exception). I've turned red several times with an artillery cannon, and I think I've seen people turn red using gas launchers.
Amazing Ace HQ: http://amazingace.wix.com/priority
We've come to a conclusion that anyone can get free napalm grenades from using explosive weapons
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