Modifiers matching fuel:

• base,
• simple,
• liquid,
• precious,
• solid,
• regular,
• abundant,
• combustible,
• natural,
• safe,
• efficient,
• common,
• organic,
• needed,
• strategic,
• clean,
• new,
• volatile,
• traditional,
• unprocessed,
• gaseous,
• chemical,
• hard,
• light,
• several,
• benign,
• familiar,
• cheap,
• odd,
• conventional,
• dirtier,
• consumable,
• major,
• cleaner,
• important,
• unconventional,
• heavier,
• usable,
• starting,
• compressible,
• supplementary,
• commonplace,
• primary,
• thermal,
• sensitive,
• diverse,
• possible,
• refined,
• desirable,
• particular,
• nuclear,
• difficult,
• homogeneous,
• discrete,
• actual,
• appropriate,
• pure,
• vaporizable,
• real,
• sustainable,
• up,
• small,
• unwanted,
• nonrenewable,
• future,
• medical,
• complex,
• fluid,
• old,
• technical,
• cryogenic,
• hazardous,
• explosive,
• destructive,
• flammable,
• renewable,
• expensive,
• foreign,
• soluble,
• inexpensive,
• rich,
• special,
• raw,
• modern,
• separate,
• extra,
• friendly,
• wet,
• synthetic,
• innovative,
• thinner,
• supporting,
• ignitable,
• competitive,
• practical,
• key,
• fibrous,
• finished,
• nonpolar,
• automotive,
• costly,
• fine,
• down,
• uniform,
• useful,
• inhomogeneous,
• off,
• vegetative,
• vehicular,
• granular,
• particulate,
• typical,
• harmful,
• dry,
• macromolecular,
• biological,
• intermediate,
• reactive,
• oxidizable,
• unhealthy,
• corrosive,
• specialized,
• secondary,
• available,
• essential,
• taxable,
• heavy,
• lighter,
• domestic,
• direct,
• damaging,
• valuable,
• miscellaneous,
• carbonaceous,
• alternative,
• local,
• nonwoody,
• physiological,
• abrasive,
• loose,
• advanced,
• artificial,
• porous,
• dirty,
• auxiliary,
• dangerous,
• metabolic,
• residual,
• motor,
• main,
• smaller,
• indoor,
• industrial,
• manufactured,
• indigenous,
• inflammable,
• beneficial,
• ordinary,
• commercial,
• single,
• supplemental,
• convenient,
• powdered,
• dense,
• standard,
• compressed,
• exotic,
• propellant,
• normal,
• individual,
• mundane,
• suitable,
• dead,
• residential,
• basic,
• environmental,
• toxic,
• herbaceous,

Simple categories matching dirty:

• fuel,
• surface,
• environment,
• process,
• air,
• paving,
• footwear,
• liquid,
• area,
• linen,
• item,
• machine,
• object,
• gear,
• dish,
• space,
• matter,
• radiator,
• location,
• job,
• activity,
• substance,
• fluid,
• room,
• material,
• work,
• place,
• particle,
• tank,
• condition,
• thing,
• implement,
• textile,
• artist,
• os,