Get Rid of "It"
 

I’m unsure which word to use for “it” at the end of my sentences below. The sentences are meant to be commands:

Get rid of it (referring to a masculine object: el libro, el chicle, el reloj)
Deshazte de él?????
Deshazte de ello?????

Get rid of it (referring to a feminine object: la pulsera, la manzana, la pantufla)
Deshazte de ella?????

Any input is appreciated.

If the object to be offloaded is an idea or an abstract, use de ello.

That's the direct translation which works, but is not commonly used. Commonly in Latin American Spanish you will hear, Bótalo.

Thanks, Rusty. That makes sense.

Thanks, poli. I'll consider using the verb "botar."

There are several verbs that can be used.

deshacerse de algo
tirar algo (a la basura)
botar algo
echar algo a la basura
sacar algo (when used in context)

I agree with all that has been said. I will just add that the expression "deshacerse de algo" is mostly used for something that is hindering or hampering, or something that may eventually become noxious. For example, if you stole the book, someone may advise you: "deshazte de él", so you won't get caught.

Thank you, Tomisimo and Angelica, for the added input.

What verb would be best to use when referring to people? For instance, after learning about a bad relationship, you might advise your close friend "to get rid of him" / "to get rid of her."

Deshazte de él????
Deshazte de ella????

Without any context, my first choice would be "aléjate de él/ella". That would be used for someone who is a bad influence or someone who means harm.

"Deshazte de él/ella" is not wrong, but the expression is charged with contempt, since you're talking about a person as if they were an object one can dump.
Talking about an employee one wants fired, you may say "deshazte de él/ella", but you may also be less harsh and instead say "córrelo" (colloquially) or "despídelo" (standard verb).
If someone is talking to your friend and you both had plans together, you may also use "deshazte de él/ella", because this third person is hampering your activities with your friend. In that case, you are definitely expressing contempt for the person who stands between you and your plans. :)

Thank you for your detailed response, Angelica. That makes it perfectly clear.