Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to clean carpet naturally [title] Use plain hot water in a steam cleaner. [step] Many carpet cleaning machines say that you should use their highly concentrated cleaner when steam cleaning your carpets. However, using plain water in these machines will get a large amount of dirt and grime out of the carpet, and it won't leave any residue or chemicals behind.

Ending1: [substeps] This method will not work on hard to clean stains. However, it is a good way to give your carpet a general, all over cleaning. Ending2: [substeps] You may also opt for a professional carpet cleaner if cleaning a large area like a patio or basement. [title] Be careful of exposing the carpet to high heat. Ending3: To start, you should use the most concentrated cleaner you can find. [substeps] Do not use machine wash with wd-40. Ending4: Follow any instructions for the machine when using them. [substeps] Some steam cleaners target the burned carpet instead of the contact fibers.

Answer format: ending1/ending2/ending3/ending4