Σαπουνίζω το πινέλο και το ξεπλένω καλά, για να μη μείνει πάνω του μπογιά.

They are doing two different jobs.

• το πινέλο = the brush. Here το is the definite article.
• το ξεπλένω = I rinse it. Here το is a weak object pronoun, meaning it.

So Greek is not repeating the brush in the second clause; it is replacing it with it.

Also, in Modern Greek, these weak object pronouns normally come before the finite verb, so το ξεπλένω is the normal order for I rinse it.

Σαπουνίζω means to soap, to lather with soap, or to wash using soap.

It comes from σαπούνι = soap. So it is a very transparent formation: basically to apply soap to something.

In this sentence, Σαπουνίζω το πινέλο means that the speaker is soaping the brush, not just generally cleaning it.

• πλένω = I wash
• ξεπλένω = I rinse / wash out / wash off

The prefix ξε- often adds the idea of:

• removing something
• undoing something
• washing something away

So here ξεπλένω suggests rinsing the brush thoroughly so that soap, paint, or residue comes off.

Because καλά is an adverb here, not an adjective.

• καλός, καλή, καλό = good as an adjective
• καλά = well as an adverb

So το ξεπλένω καλά means I rinse it well / thoroughly.

This is very common in Greek: the adverb often has the same form as the neuter singular adjective.

Για να introduces a purpose clause. It means:

• so that
• in order to

So για να μη μείνει πάνω του μπογιά explains the purpose of rinsing the brush well: the speaker does it so that no paint remains on it.

This structure is extremely common in Greek:

• κάνω κάτι για να... = I do something so that...

Because μη is the negative particle used with subjunctive-type structures and other non-indicative contexts, while δεν is used with the indicative.

After για να, Greek uses the subjunctive, so the negative must be μη.

Compare:

• μένει = it remains → indicative, so you negate it with δεν
• να μείνει = to remain / that it remain → subjunctive, so you negate it with μη

That is why the sentence has:

• για να μη μείνει...

not

• για να δεν μένει...

Μείνει is the aorist subjunctive form of μένω = I remain / stay.

After να, Greek often uses subjunctive forms, and here the aorist subjunctive fits well because it focuses on the result:

• να μη μείνει μπογιά = so that no paint is left

It is not talking about an ongoing state in a descriptive way; it is talking about avoiding the result of paint remaining on the brush after rinsing.

Very roughly:

• μένει = indicative, it remains / is remaining
• να μείνει = subjunctive, to remain / be left

Πάνω του means on it or literally on top of it.

The του here is a weak genitive pronoun referring back to το πινέλο.

This may look strange to an English speaker, but in Greek, expressions like these are very common:

• πάνω του = on it / on him
• μέσα του = inside it / inside him
• δίπλα του = next to him / next to it

Because πινέλο is neuter singular, the corresponding genitive weak pronoun is του.

So:

• πάνω του = on the brush / on it

Because μπογιά here is being used in a general, indefinite sense: paint as a substance or residue.

So να μη μείνει πάνω του μπογιά means:

• so that no paint remains on it
• so that paint is not left on it

If you added the article, η μπογιά, it could sound more specific, like the paint in a particular context. Without the article, it sounds natural and general.

This is common in Greek, especially with mass nouns and after negatives.

Yes, the present tense here can naturally describe:

• a habitual action
• a procedure
• a demonstration
• a step-by-step explanation

So Σαπουνίζω... και το ξεπλένω... can mean something like:

• I soap the brush and rinse it well...
• What I do is soap the brush and rinse it well...

Greek uses the present tense this way very often, just like English can in instructions or demonstrations.

If this were a direct command, Greek would probably use the imperative instead.

No, Greek word order is fairly flexible.

This sentence is perfectly natural, but you could also hear:

• για να μη μείνει μπογιά πάνω του

Both mean the same thing.

The version in your sentence places μπογιά at the end, which can make paint feel like the final, important piece of information. Greek often moves elements around for rhythm, focus, or emphasis more freely than English does.