Trashcore is a VERY new subculture, with a VERY small scene. But its growing and might be huge someday you never know.

[edit] Steps

Trashcore combines punk, metal, goth, and every other form of subculture that may be frowned upon by society. Hence the trash part, we are the trash of society, the people you threw away and left as good for nothing.
First, trashcore music: Trashcore music is mostly based on classic punk roots, taking a decent chunk of influence from hardcore, a little bit of post punk/alternative, mixing in a little vintage metal, some death/thrash/doom metal, influences, funk, psychedelic, new wave, lyrics that don't necessarily rhyme, And random sporadic key changes, or even the total lack of key.
Trashcore style of dressing: anything that isnt popular. Go to the mall and make a list of the most commonly warn clothing by the scene kids, mallgoths, mallpunks, preps, and whatever else is there. then dont wear the clothes.
For hair get it either shaved off or very long. jeans are good for pants, or khakis, anything ripped is good, things with patches and pins are good too.
The most important part of trashcore, is not conforming to the trends of people who think their counterculture.