ayo,rma means rosak d ma...then agak agak wrap lo..haha...just joking..
better use bubble wrap,then another layer of cardboard,then newspaper,then only the brown paper.
that will do it.
and that's what i usually do!!

even if use pos express,i sugget u staple the seal + cellotape it...
that's what i do..super diff to open it...hehe..

not all pos office u can get the plastic bag(they call it flyer)..
only certain poslaju center has it..limited oso..