US 2016/0251602 Al  21  Sep. 1, 2016  20.  The method according to any one of the preceding  claims wherein the method comprises moving the metal sub› strate such that its surface is brought into contact with the  solid particles.  21.  The method according to any one of the preceding  claims wherein the method comprises rotating, oscillating or  reciprocating the metal substrate within the cleaning liquor.  22.  The method according to any one of the preceding  claims wherein the method comprises scouring the surface of  the metal substrate with the solid particles.  23.  The method according to any one of the preceding  claims wherein the method comprises agitating the solid par› ticles within the cleaning liquor.  24.  The method according to any one of the preceding  claims wherein the method is carried out using a fluidized bed  containing the cleaning liquor.  25.  The method according to any one of the preceding  claims wherein the cleaning liquor contacts the metal surface  at a relative velocity of at least 1 cm per second.  26.  The method according to any one of the preceding  claims wherein the multiplicity of solid particles comprises or  consists of a multiplicity of polymeric particles or wherein  the multiplicity of solid particles comprises or consists of a  multiplicity of non-polymeric particles.  39.  The method according to any of claims  26  to  37  wherein the polymeric particles comprise particles selected  from linear, branched or cross-linked polymers.  40.  The method according to any of claims  26  to  37  and  claim  39  wherein the polymeric particles comprise foamed or  unfoamed polymers.  41.  The method according to any one of the preceding  claims wherein the solid particles are ofhollow and/or porous  construction.  42.  The method according to any of claims  26  to  37  or  claims  39  and  40  wherein the polymeric particles have an  average density of from about 0.5 to about 3.5 g/cm 3 •  43.  The method according to claim  26, 27  or  38,  wherein  the non-polymeric particles have an average density of from  about 3.5 to about 12.0 g/cm 3 •  44.  The method according to any of claims  26  to  43  wherein the polymeric or non-polymeric particles have an  average volume in the range of about 5 to about 27 5 mm 3 •  45.  The method according to any one of the preceding  claims wherein the solid particles are reused one or more  times for cleaning of metal substrates according to the  method of the invention.  46.  The method according to any one of the preceding  claims wherein the method comprises a step of recovering the  multiplicity of solid particles after cleaning of the metal sub› strate.  47.  The method according to any one of the preceding  claims wherein the cleaning formulation comprises one or  more components selected from the group consisting of: sol› vents, polymers, corrosion inhibitors, builders, chelating  agents, surfactants, dispersants, acids, bases, anti-oxidants,  reducing agents, oxidising agents and bleaches.  48.  The method according to any one of the preceding  claims wherein the method further comprises coating the  metal substrate after cleaning the metal substrate.  49.  The method according to any one of the preceding  claims wherein the metal substrate comprises a transition  metal.  50.  The method according to any one of the preceding  claims wherein the metal substrate comprises aluminum.  51.  The method according to any one of the preceding  claims wherein the metal substrate is a metal alloy.  52.  The method according to claim  51  wherein the metal  alloy is an alloy of iron.  53.  The method according to any one of the preceding  claims wherein the metal substrate comprises a metal sheet.  54.  The method according any one of the preceding claims  wherein the metal substrate is a can.  55.  A method of treating a metal substrate comprising the  steps of:  56.  The method according to claim  55  wherein step b)  comprises exposing the metal substrate to a treatment liquor  comprising a treatment formulation and a multiplicity of solid  particles.  57.  The method according to claim  56  wherein the method  further comprises causing the solid particles and the metal  substrate to enter into contacting relative movement.  38.  The method according to claim  26  or  27  wherein the  non-polymeric particles comprise particles of ceramic mate› rial, refractory material, igneous, sedimentary, metamorphic  minerals or composites.  37.  The method according to claim  35  wherein the polyes› ter particles comprise particles of polyethylene terephthalate  or polybutylene terephthalate.  36.  The method according to claim  35  wherein the polya› mide particles comprise particles of nylon.  35.  The method according to any of claims  26  to  29,  claim  31  or claim  32  wherein the polymeric particles comprise  particles selected from polyamide, polyester or copolymers  thereof.  34.  The method according to claim  33  wherein the poly› meric particles comprise particles of polypropylene.  33.  The method according to any of claims  26  to  28  or any  of claims  30  to  32  wherein the polymeric particles comprise  particles selected from particles of polyalkenes or copoly› mers thereof.  32.  The method according to any of claims  26  to  31  wherein the polymeric particles comprise particles selected  from particles of polyalkenes, polyamides, polyesters, pol› ysiloxanes, polyurethanes or copolymers thereof.  31.  The method according to any of claims  26  to  28  wherein the polymeric particles comprise particles of one or  more polar polymers and particles of one or more non-polar  polymers.  30.  The method according to any of claims  26  to  28  wherein the polymeric particles comprise particles of one or  more non-polar polymers.  29.  The method according to any of claims  26  to  28  wherein the polymeric particles comprise particles of one or  more polar polymers.  27.  The method according to any one of the preceding  claims wherein the multiplicity of solid particles comprises or  consists of a mixture of a multiplicity of polymeric particles  and a multiplicity of non-polymeric particles.  28.  The method according to any one of the preceding  claims wherein the multiplicity of solid particles comprises or  consists of a multiplicity of polymeric particles.  a) cleaning the metal substrate to remove contaminants  according to any of claims  1  to  54;  b) removing at least a portion of an oxide layer from the  surface of the cleaned substrate. 