Per pulire il tavolo, devo strofinare bene la macchia.

In this sentence, per + infinitive expresses purpose.

So:

• per pulire = to clean / in order to clean
• Per pulire il tavolo = To clean the table

Literally, per often means for, but with an infinitive it very often means in order to.

Examples:

• Per capire, devo leggere lentamente. = To understand, I have to read slowly.
• Per arrivare in tempo, dobbiamo partire adesso. = To arrive on time, we have to leave now.

Because each one depends on another structure:

• per pulire: after per to show purpose, Italian uses the infinitive
• devo strofinare: after dovere (must / have to), the next verb also stays in the infinitive

So the only conjugated verb here is:

• devo = I have to

And the action verbs stay unconjugated:

• pulire = to clean
• strofinare = to rub / scrub

This is very similar to English:

• I have to rub
• not I have to rubs

Devo is the first-person singular present of dovere.

• dovere = must / to have to
• devo = I must / I have to

So:

• devo strofinare = I have to scrub or I must scrub

In everyday Italian, dovere is used a lot for obligation, necessity, or what is needed in a situation.

Examples:

• Devo studiare. = I have to study.
• Devo andare. = I have to go.

They are not the same action.

• pulire = to clean
  This is the overall goal or result.
• strofinare = to rub / scrub
  This is the specific action used to achieve that goal.

So the sentence means something like:

• To clean the table, I have to scrub the stain well.

In other words:

• pulire il tavolo = the goal
• strofinare la macchia = the method

Macchia usually means:

• stain
• spot
• mark

In this sentence, la macchia most naturally means the stain or the mark on the table.

So:

• strofinare bene la macchia = to scrub the stain well

Depending on context, macchia can refer to something small and visible left on a surface.

Because the sentence is focusing on the part that needs extra action.

You clean the table by rubbing the stain. So the direct object of strofinare is la macchia, not il tavolo.

Compare:

• Devo strofinare bene la macchia. = I have to scrub the stain well.
• Devo strofinare bene il tavolo. = I have to scrub the table well.

Both are grammatical, but they mean slightly different things. The original sentence is more specific: the problem is the stain.

Italian uses definite articles very regularly, often more than English does.

Here:

• il tavolo = the table
• la macchia = the stain

This sounds natural in Italian because the speaker is talking about a specific table and a specific stain.

If it were indefinite, you might say:

• una macchia = a stain

But in the original sentence, la macchia suggests a known or visible stain: the stain we are dealing with.

Bene is an adverb meaning:

• well
• properly
• thoroughly, depending on context

So:

• strofinare bene = to rub well / scrub thoroughly

It modifies the verb strofinare, telling you how the action should be done.

In this sentence, bene gives the idea that a quick or weak rub is not enough.

That is the normal and natural position for an adverb like bene.

• strofinare bene la macchia = to scrub the stain well

Italian often places adverbs like bene, male, molto, etc. after the verb or verb phrase.

You may hear other word orders in some contexts, but this one is straightforward and standard.

Yes. If the stain has already been mentioned, Italian would often use a direct object pronoun.

You can say:

• Devo strofinarla bene.
• La devo strofinare bene.

Both mean:

• I have to scrub it well.

With infinitives, Italian allows two common placements:

1. before the conjugated verb
   La devo strofinare
2. attached to the infinitive
   Devo strofinarla

Both are correct.

Not strictly.

You can write:

• Per pulire il tavolo, devo strofinare bene la macchia.
• Per pulire il tavolo devo strofinare bene la macchia.

Both are acceptable.

The comma is often used because Per pulire il tavolo is an introductory purpose phrase, and the comma makes the sentence easier to read. But it is not mandatory in every case.

Yes. Italian word order is fairly flexible.

For example:

• Devo strofinare bene la macchia per pulire il tavolo.

This is also grammatical and means essentially the same thing.

The original version puts the purpose first:

• Per pulire il tavolo... = To clean the table...

That structure is very natural when you want to emphasize the goal before explaining what must be done.