Limpio el filtro de pelusa y seco la ropa al aire.

Because this sentence is describing what I do, not naming the actions in general.

• limpio = I clean
• seco = I dry

These are both in the first-person singular present tense.

So:

• Limpiar el filtro de pelusa = To clean the lint filter
• Limpio el filtro de pelusa = I clean the lint filter

In many everyday contexts, the Spanish present tense can describe:

• a habitual action: I clean the lint filter and air-dry the clothes
• a routine: I clean the lint filter and dry the clothes in the air

Spanish often omits subject pronouns when the verb ending already makes the subject clear.

• limpio already tells you the subject is yo
• seco also already tells you the subject is yo

So yo is usually unnecessary unless you want emphasis or contrast.

For example:

• Limpio el filtro de pelusa... = normal, neutral
• Yo limpio el filtro de pelusa... = more emphatic, like I’m the one who cleans it

This is very common in both Spain and Latin America.

Here, seco is a verb: I dry.

It comes from the verb secar.

• secar = to dry
• seco = I dry

This can be confusing because seco is also an adjective meaning dry in other contexts:

• El clima es seco. = The climate is dry.
• Estoy seco. = I am dry or sometimes colloquially I’m broke depending on context

In your sentence, it is definitely a verb because it is followed by a direct object:

• seco la ropa = I dry the clothes

Spanish often uses the definite article (el, la, los, las) where English might use my, your, his, etc., especially when ownership is obvious from context.

So:

• Limpio el filtro de pelusa literally = I clean the lint filter
• seco la ropa literally = I dry the clothes / the laundry

Even if it is your lint filter or your clothes, Spanish often prefers the article if no confusion exists.

Using mi is possible, but it can sound more specific or emphasized:

• Limpio mi filtro de pelusa = I clean my lint filter
• Seco mi ropa al aire = I air-dry my clothes

The version with el/la sounds very natural for general routine statements.

It is a noun + de + noun structure, which is very common in Spanish.

• filtro = filter
• pelusa = lint, fluff, fuzz

So:

• filtro de pelusa = lint filter or lint trap

The word de here works a bit like of in English, but in natural translation you usually do not say filter of lint. You say lint filter.

This pattern is extremely common:

• taza de café = cup of coffee
• jugo de naranja = orange juice
• cepillo de dientes = toothbrush

Because al is the contraction of a + el.

• a + el = al

So:

• seco la ropa al aire

This comes from the expression secar al aire, which means to air-dry.

A very important note: this contraction happens almost always with a + el.

Examples:

• Voy al mercado. = I go to the market.
• Pongo la silla al lado de la mesa. = I put the chair beside the table.

But there is no contraction with a + la:

• Voy a la tienda.

Here, al aire means by air / in the air, but in natural English the idea is air-dry.

So secar la ropa al aire means:

• dry clothes naturally instead of using a dryer
• let them dry by exposure to air

It does not always mean outdoors. The clothes could dry:

• outside on a clothesline
• inside on a drying rack

If you specifically want to say outdoors, Spanish often uses al aire libre.

So:

• secar la ropa al aire = to air-dry the clothes
• secar la ropa al aire libre = to dry the clothes outdoors

Because ropa is a collective singular noun in Spanish.

Even though it refers to multiple items, Spanish treats it grammatically as singular:

• la ropa = clothes / clothing / laundry

So you say:

• La ropa está limpia. = The clothes are clean.
• Seco la ropa. = I dry the clothes / laundry.

English often uses a plural word (clothes), but Spanish uses the singular ropa.

If you want to talk about individual garments, you might use:

• las prendas = garments/items of clothing
• la ropa = clothing/clothes/laundry in general

It can be either, depending on context.

The present tense in Spanish can express:

1. a habitual action / routine
2. what someone is doing now, in some contexts

So this sentence could mean:

• I clean the lint filter and air-dry the clothes.
  habitual / routine

Depending on context, it could also be understood as:

• I’m cleaning the lint filter and air-drying the clothes.

However, if you want to make right now especially clear, Spanish often uses the progressive:

• Estoy limpiando el filtro de pelusa y secando la ropa al aire.

That said, the simple present is very common for routines.

Yes, it is understandable and natural, especially as a general statement. Secar la ropa al aire is a normal way to express air-drying clothes.

That said, depending on the country or situation, you might also hear other natural options, such as:

• tiendo la ropa = I hang the clothes up
• dejo secar la ropa al aire = I let the clothes air-dry
• pongo la ropa a secar = I put the clothes out to dry

Also, for lint filter, some speakers may use slightly different wording depending on the appliance and region, but filtro de pelusa is clear and widely understandable.

There actually is an article there, but it is hidden inside al.

• al = a + el

So al aire literally contains el aire.

That is why you do not see a el aire. Spanish contracts it:

• a el aire → al aire

So the article is still present, just merged into al.