effect help

[danacm]

Hi!

I created a spell, which leaves poison trail behind the caster, i use dummy unit which attack ground with burning oil, but i dont like the burning oil effect, so i creating effect in the looping trigger, but i cant destroy the effect via timer.pls help me!!

i attached the test map.

 

[Maker]

There.

 

[danacm]

Ty for help!!!!