They ai't trash. They are good words of English heritage.
Ain't:
Originally a contraction of am not, and considered proper as such until in early 19c. it began to be also a generic contraction of are not, is not, has not, etc. This was popularized in representations of London cockney dialect in Dickens, etc., which led to the word being banished entirely from correct English.
Trash:
c. 1400, "fallen leaves, brush, and twigs used as kindling;" also "things of little use or value" collectively; "waste, refuse, dross; something broken or torn to bits, tattered garment;"