Muszę wyczyścić kuwetę przed wyjściem z domu, bo później nie będę mieć czasu.

Muszę is the 1st person singular present-tense form of musieć = to have to / must.

So:

• muszę = I have to / I must
• musisz = you have to
• musi = he/she/it has to

In Polish, a form like muszę already tells you the subject is I, so you do not need to add ja unless you want emphasis.

After musieć, Polish normally uses an infinitive:

• muszę zrobić = I have to do
• muszę iść = I have to go
• muszę wyczyścić = I have to clean

So muszę wyczyścić kuwetę literally works like I have to clean the litter box.

This is about aspect, which is very important in Polish.

• czyścić = to be cleaning / to clean in an ongoing, repeated, or unfinished sense
• wyczyścić = to clean up completely / to finish cleaning

Here, wyczyścić is used because the speaker means a completed action: the litter box should be cleaned before leaving.

Compare:

• Muszę czyścić kuwetę codziennie. = I have to clean the litter box every day.
  (habit, repeated action)
• Muszę wyczyścić kuwetę przed wyjściem. = I have to clean the litter box before leaving.
  (one completed task)

Because kuweta is the direct object of wyczyścić, so it must be in the accusative case.

• nominative: kuweta
• accusative: kuwetę

Since kuweta is a feminine noun ending in -a, its accusative singular usually changes -a to -ę.

Compare:

• To jest kuweta. = This is a litter box.
  (nominative)
• Czyszczę kuwetę. = I am cleaning the litter box.
  (accusative)

Kuweta can mean a tray-like container, but in everyday pet-related context it usually means a litter box.

So in this sentence, the most natural meaning is the cat’s litter box.

Depending on context, kuweta can also mean other kinds of trays or pans, but for most learners this word is worth remembering mainly as litter box.

Because przed here means before, and after przed, Polish uses the instrumental case.

The base word is:

• wyjście = exit / leaving / going out

In the instrumental singular, it becomes:

• wyjściem

So:

• przed wyjściem = before leaving / before the departure

This is a very common Polish structure: a preposition + a verbal noun.

It is a noun, specifically a verbal noun formed from the verb wyjść = to go out / leave.

• wyjść = to leave
• wyjście = leaving / exit / departure

Polish often uses these verbal nouns where English might use an -ing form:

• przed wyjściem = before leaving
• po powrocie = after returning
• bez mówienia = without speaking

So even though wyjściem looks noun-like, it functions here much like English leaving.

Because z in the sense of from / out of takes the genitive case.

So:

• dom = house/home
• domu = genitive form

That gives:

• z domu = from the house / from home

Be careful: Polish z can govern different cases depending on meaning.

• z domu = from the house/home → genitive
• z kolegą = with a friend → instrumental

Here the meaning is movement away from home, so genitive is required.

Because bo introduces a new clause explaining the reason, and in standard Polish punctuation you put a comma before it.

So:

• Muszę wyczyścić kuwetę przed wyjściem z domu, bo później nie będę mieć czasu.

This is similar to English writing a comma before because in some sentence structures, though Polish comma rules are generally stricter with clauses.

Both can mean because, but they differ in tone.

• bo = very common, everyday, natural in speech
• ponieważ = a bit more formal or written

So this sentence sounds natural and conversational with bo.

Compare:

• Muszę iść, bo jest późno. = I have to go, because it’s late.
• Muszę iść, ponieważ jest późno. = same meaning, but more formal

Both patterns are correct.

For mieć in the future, Polish commonly uses:

• będę mieć
• będę miał / będę miała

So these are both possible:

• Nie będę mieć czasu.
• Nie będę miał czasu. / Nie będę miała czasu.

The version with mieć + infinitive is especially useful because it does not show gender.
The version with miał / miała does show gender:

• będę miał = speaker is masculine
• będę miała = speaker is feminine

That is one reason learners often see będę mieć in example sentences.

Because after negation, Polish often changes the direct object into the genitive case.

Affirmative:

• Będę mieć czas. = I will have time.

Negative:

• Nie będę mieć czasu. = I will not have time.

So:

• czas = accusative/nominative form
• czasu = genitive form

This is a very common pattern in Polish:

• Mam samochód. = I have a car.
• Nie mam samochodu. = I don’t have a car.

Because Polish usually omits subject pronouns when the verb form already makes the subject clear.

• muszę already means I must
• będę already means I will

So ja is unnecessary unless you want emphasis or contrast:

• Ja muszę wyczyścić kuwetę. = I have to clean the litter box.
  (maybe not someone else)

In neutral sentences, leaving out ja is more natural.

Yes, Polish word order is quite flexible, although some orders sound more natural than others.

The given sentence is very natural:

• Muszę wyczyścić kuwetę przed wyjściem z domu, bo później nie będę mieć czasu.

You could also say:

• Przed wyjściem z domu muszę wyczyścić kuwetę, bo później nie będę mieć czasu.

This puts extra focus on before leaving home.

Or:

• Muszę wyczyścić kuwetę, bo później nie będę mieć czasu. Zrobię to przed wyjściem z domu.

That splits the idea into two sentences.

So the meaning stays similar, but the emphasis changes.

In z domu, it often means from home as much as from the house.

Polish dom can mean both:

• the physical house
• the idea of home

So wyjście z domu is very often best understood as leaving home, even though the literal wording is leaving the house.