1) Rubber glove.
2) 2nd rubber glove but filled with finely ground salt.
3) Insert golve 1 into glove 2, use tape to seal.
>Ghost can't phase through hand.
<Might not hurt them much though, since they could probably make an emergency hole in themself.
>A tennis racket or similar could potentially be modified into an anti-ghost melee using similar methods. Bigger the surface, Harder the smack.