Instrumental case in the Polish language. Am I understanding it right?

Thank you Ziemowit. Are these 5 sentences grammatically correct? "Jem ryż widelcem/łyżką", "Nie jem zup(y) widelcem", "Nie jem baton(ik)u/baton(ik)ów ani widelcem, ani łyżką", "Zaśpiewałem rockową piosenkę/rockowe piosenki basem" and "Nie zaśpiewałem piosenki/piosenek opery sopranem"

There's also gardzić (czymś) - to despise

Gardzę takimi ludźmi...

Gardzi dorszem.... (s/he despises cod...)

@ForumUser
About 'batonik' :)

Piosenki rockowe sounds more natural than rockowe piosenki - I don't know the rule behind it, though.
Also: 'pieśni or arie operowe' rather than piosenki.

Supposedly there are more of them.


I tend to disagree. Both sound OK.

And I forgot to post the link about batonik.
Anyway, it's jeść batonik, nie jeść batonika.

Thank you kaprys. I guess I thought singular genitive case/declension "batoniku" because masculine inanimate singular genitive ends in either Letter A or U. I do know that sometimes but not always, if masculine inanimate singular locative & vocative declension already ends in Letter U, then the corresponding singular genitive declension will sometimes end in Letter A instead of U, hence I selected wrong ending. What are some general guidelines in how to determine whether masculine inanimate singular genitive ends in either Letter A or U? Or generally do most end Letter U? - especially most whose corresponding singular locatives & vocatives end in "Softened Final Consonant + E"?

Similarly, oglądać salonik, not salonika.

In the Polish counterpart of the English-language sentence structures "Affirmative Sentence + Neither...Nor" such as "I eat candy bar(s) with neither fork nor spoon" and "Negated Sentence + Either..Or" such as "I don't (ever) eat candy bar(s) with either fork or spoon",

In Polish sentences is it only negated verbs? Is this the correct Polish-language sentence structure "(Nigdy) Nie + Ani..., Ani"? Hence, is this sentence grammatically correct? "(Nigdy) Nie jem batonu/batonika/baton(ik)ów ani widelcem, ani łyżką"?