Hullet tøj lægger vi i en særskilt pose, indtil vi finder ud af, om noget af det kan repareres.

Because Danish main clauses normally follow the V2 rule: the finite verb comes in the second position.

Here, Hullet tøj has been moved to the front to make it the topic:

• Hullet tøj lægger vi ...

The more neutral order would be:

• Vi lægger hullet tøj i en særskilt pose ...

When the object is placed first, the subject moves after the verb:

• Hullet tøj
  • lægger
    • vi

This is very common in Danish.

Because tøj is grammatically singular in Danish, even though it refers to clothes in a general sense.

So the adjective stays in its singular indefinite form:

• hullet tøj

The form hullede is used for plural or definite forms, for example:

• de hullede sokker
• det hullede tøj may also occur in definite use, but hullede is the common plural/definite-style form learners will often meet with countable nouns.

Also, hullet is the normal adjective for full of holes / holey.

Because tøj is usually treated as an uncountable mass noun, like clothing in English.

So Danish normally says:

• tøj = clothes/clothing in general

Not:

• et tøj for this meaning

That is why hullet tøj appears without en or et.

This is just a difference between the two languages.

In Danish:

• tøj is a singular mass noun

In English:

• clothes is plural

That is why Danish later refers back to it with det rather than a plural pronoun:

• noget af det

So even though the meaning is plural in real life, the grammar is singular in Danish.

Yes, lægge basically means lay / put down / place.

Danish often uses lægge for putting things somewhere, especially things that are soft, flat, or naturally thought of as lying somewhere, such as clothes.

So:

• lægger vi i en særskilt pose = we put in a separate bag

You could also hear putter in everyday speech, but lægger sounds very natural here.

Særskilt means separate, distinct, or kept apart.

So:

• en særskilt pose = a separate bag

It is en because pose is a common-gender noun in Danish:

• en pose
• not et pose

So the phrase is grammatically:

• en særskilt pose

Finde ud af is a very common Danish expression meaning:

• find out
• figure out
• determine

It works as a fixed expression, so the af belongs with the verb phrase.

Examples:

• Jeg skal lige finde ud af det. = I just need to find that out / figure that out.
• Vi finder ud af, om ... = We find out whether ...

So you should learn finde ud af as a whole unit.

Because om here means whether / if in an indirect question.

The sentence is asking about a possibility:

• whether some of it can be repaired

So Danish uses:

• om

By contrast, hvis is used for conditional if:

• Hvis det regner, bliver vi hjemme. = If it rains, we stay home.

So:

• Vi finder ud af, om ... = We find out whether ...
• not Vi finder ud af, hvis ...

Noget af det literally means something of it, but in natural English it is usually:

• some of it
• any of it

The det refers back to tøj.

Because tøj is grammatically singular, Danish uses:

• det = it

Not a plural pronoun.

So:

• om noget af det kan repareres = whether any of it can be repaired

Because Danish often uses the -s passive.

So:

• kan repareres literally = can repair-s
• natural English = can be repaired

This is a very common Danish way to form the passive, especially after modal verbs like:

• kan
• skal
• må

You can also say:

• kan blive repareret

But kan repareres is shorter and very natural here.