A method of operating and cleaning a compressor comprising the following steps: passing a first fluid through the compressor, the first fluid comprising gas from a separator wherein the compressor is operating to compress the first fluid passed therethrough, mixing well fluid bypassed from upstream of the separator with the gas from the separator to produce a second fluid comprising gas and liquid wherein the gas and liquid are from at least one well; and passing the second fluid through the compressor, wherein the second fluid is passed through the compressor for a limited time period to clean a surface inside the compressor, the compressor operating to compress the second fluid passed therethrough.