myjniach

In a sentence

• Samochody są czyste, ponieważ były umyte w automatycznych myjniach.

  The cars are clean because they were washed in automatic car washes.

  In this sentence, 'myjniach' refers to the place (car washes) where cars are washed.

• W naszej okolicy jest wiele różnych myjni, ale rzadko korzystam z ich usług.

  In our area, there are many different car washes, but I rarely use their services.

  Here, 'myjniach' implies places providing car-washing services, though the noun itself is in singular and not used directly in the "myjniach" form unless applicable in a different inflected context.

• Na stacjach benzynowych często spotyka się małe myjnie.

  Small car washes are often encountered at gas stations.

  In this case, 'myjniach' is implied as the plural dative or locative case, but here the context is more broad, referring to the presence of such places.