Improvement in separating lower carboxylic acids from aqueous streams via liquid-liquid extraction with pressurized liquefied propylene andor propane, wherein carboxylic acid is transferred from the aqueous phase into the liquid solvent phase. The methods for cleaning patterned substrate have advantages in cleaning patterned substrates with fine features without substantially damaging the features by using the cleaning materials described. Each coil defines an axis, wherein the axes of the first coil and the second coil are orthogonal to each other. In one embodiment, a printer is provided that is configured to generate fingerprints for paper sheets loaded into the printer prior to the paper sheets being available for printing.