The government should give illegals 6 months to sell everything, they don't want to take with them, and to return to their home countries. In the meantime we make a concerted effort to enforce the laws, already on the books, against employing illegals. Then, in 6 months, law enforcement goes door-to-door to mop up. Any illegal apprehended, at that time, forfeits all.
We should start walling off the borders and patrolling them militarily so that, once the illegals are out, they stay out.