У этой блузки очень тонкая ткань, поэтому её лучше стирать вручную.

У + genitive is a very common Russian way to express possession or a characteristic of something.

So У этой блузки очень тонкая ткань literally feels like:

• At this blouse / with this blouse, the fabric is very thin

But in natural English, that becomes:

• This blouse has very thin fabric
• or This blouse is made of very thin fabric

Russian often prefers this у + genitive structure where English would use have.

Because the preposition у requires the genitive case.

• dictionary form: эта блузка
• after у: у этой блузки

So:

• эта блузка = this blouse
• у этой блузки = of/with this blouse

This is just standard case government: у takes the genitive.

Because ткань is a feminine singular noun, and the adjective has to agree with it.

• ткань = fabric, cloth
• feminine
• singular
• nominative here, because it is the subject of the first clause

So the adjective also becomes feminine singular nominative:

• тонкий → masculine
• тонкая → feminine
• тонкая ткань = thin fabric

And очень simply means very:

• очень тонкая ткань = very thin fabric

Поэтому means therefore, so, or that’s why.

It connects the first idea and the consequence:

• The fabric is very thin, therefore it is better to wash it by hand.

The comma is used because Russian is joining two clauses:

• У этой блузки очень тонкая ткань, поэтому её лучше стирать вручную.

This punctuation is very normal in Russian.

Here её means it, referring to блузку (the blouse), which is feminine in Russian.

So:

• блузка = feminine noun
• direct object pronoun = её

In English we say wash it by hand, but in Russian the pronoun matches the grammatical gender of the noun:

• стирать блузку → стирать её

Even though the first clause mentions ткань too, the intended thing being washed is clearly the blouse, not “the fabric” as an abstract material.

Russian word order is flexible, and object pronouns are often placed before the infinitive in this kind of sentence.

So её лучше стирать вручную is a very natural way to say:

• it is better to wash it by hand

You could also hear variations, but this order sounds smooth and standard.

The important part is:

• лучше стирать её and её лучше стирать are both understandable,
• but её лучше стирать is especially natural in this sentence.

Лучше + infinitive means it’s better to...

So:

• её лучше стирать вручную = it’s better to wash it by hand

This expresses a recommendation, not a strict obligation.

Compare:

• её лучше стирать вручную = it’s better to wash it by hand
• её надо стирать вручную = it must/needs to be washed by hand
• её нужно стирать вручную = it needs to be washed by hand

So лучше sounds softer and more like practical advice, which fits clothing-care instructions well.

Стирать is imperfective, and that is the natural choice here because the sentence gives a general care instruction.

It means something like:

• When washing it, it is better to do it by hand
• It is best washed by hand

Russian often uses the imperfective for repeated, general, or habitual actions.

If you used постирать, that would sound more like wash it once / complete the washing, which is less natural for a general statement about how the blouse should be treated.

So:

• лучше стирать вручную = better to wash by hand (general advice)
• лучше постирать вручную = better to wash it by hand this one time

Yes. Вручную is a standard way to say by hand.

So:

• стирать вручную = to wash by hand

It is commonly used for manual action, especially in instructions:

• писать вручную = write by hand
• сделано вручную = made by hand
• стирать вручную = wash by hand

For clothing labels and care instructions, вручную is very natural.

Yes, Russian has other ways to express similar ideas, but У этой блузки очень тонкая ткань is very natural.

For example, you might also see things like:

• Эта блузка с очень тонкой тканью
• Эта блузка сделана из очень тонкой ткани

But those versions are slightly different in nuance or style.

The original sentence is a simple, idiomatic way to say that this blouse has the property of having very delicate fabric.

It usually means fabric or material in this context.

So here:

• тонкая ткань = thin/delicate fabric

Depending on context, ткань can also mean cloth, but for clothing descriptions fabric is usually the best translation.

In this sentence, тонкая does not necessarily mean just physically thin; it can also suggest delicate, which explains why hand washing is recommended.

It sounds like advice/recommendation, not a hard command.

That comes mainly from лучше:

• её лучше стирать вручную = it’s better to wash it by hand

So the tone is:

• practical
• cautionary
• like clothing-care advice

If Russian wanted to sound more categorical, it might use:

• нужно
• надо
• or a passive instruction style

But the original sentence is softer and very natural.