Questions & Answers about Si la olla está muy sucia, prefiero limpiarla con un estropajo.
The accent mark shows the correct stress: es-TÁ. It also distinguishes the verb form está from esta, which can mean this. In standard Spanish, the verb está always has the written accent.
In Spanish, a singular countable noun usually needs an article or another determiner. So si olla está muy sucia would be ungrammatical. You need la olla, una olla, esta olla, and so on.
Here la olla means the pot.