David Hickson melted down the knife he said that he had used to stab and kill Campbell Paterson, a court has been told.
In his police interview, Hickson said he melted it so he did not have to look at it any more, The Cairns Post reported.
The police interview was played to the Cairns Supreme Court during Hickson's trial this week.
Hickson, 34, is accused of murdering Mr Paterson.
Mr Paterson's dismembered body was found in a large chilly bin in bushland at Edmonton, about 15km southeast of Cairns on November 19, 2014.
He had not been reported missing but police became concerned after Mr Paterson failed to appear in a Cairns court twice in October 2014.
Hickson, 32 has pleaded guilty to interfering with a dead body but not guilty to murder saying it was self-defence.
Hickson described his actions as "fight or flight", The Cairns Post reported.
The court was told he'd believed Mr Paterson had meant him harm.
Hickson told police Mr Paterson had arrived at his Edmonton home on November 6 and had started using tarps and fishing nets to enclose the back yard.
"He (Mr Paterson) was making out like he was making it safe ... to me I was getting caged in," Hickson told police.
On the morning of November 7 Hickson said he and Mr Paterson were both in the lounge area and "we both reached for something at the same time and he was slower than I was I guess".
Hickson said he grabbed a hunting knife with a serrated blade about 40cm in length in total. "I've just reacted," he told police. "It just happened that quick.
"I just swung it ... got him where I shouldn't have got him."
Hickson indicated to police the knife had struck Mr Paterson in the neck. He said Mr Paterson stumbled and ended up in the bathroom holding his neck.
"I sort of put my hands over his hands," Mr Hickson said.
When asked by the police why he didn't call 000, Mr Hickson said, "Cause I was not in a ... I can't explain why I didn't call 000."