US 2016/0251602 Al  10  Sep. 1, 2016  Experiment 2  Aluminum Cleaning & Oxide Removal Using an  Apparatus Fitted with Pumping Means  TABLE 2-continued  TABLE3  TABLE4  beads, water, citrate and the non-ionic surfactant demon› strated a significant decrease in the aluminum oxide area (%)  and a significant increase in the aluminum metal area  (%) for  the surface of the metal substrate compared to the controls  (i.e. cans 1, 2 and 3) and compared to the treatment with nylon  beads and water alone (can 4). Furthermore, an aluminum  oxide layer of significantly reduced thickness was obtained  for can 5 (5.36 nm) compared to the controls and when  compared to the treatment with nylon beads and water.  [0168]  The data shown in Table 2 illustrates the results of  XPS analysis for the amount of aluminum metal and carbon  on the can surface following the various treatments. The  amount of carbon can serve as a surrogate measure for the  presence of contaminants (e.g. smut). A higher aluminum/  carbon ratio as indicated in Table 2 thus indicates that more  aluminum is present on the can surface and that more carbon  or contaminant residue has been removed. All of the cans  treated with the polymeric particles (i.e. cans 4 to 7) show an  increase in aluminum/carbon ratio compared to the controls  ( cans 1 to 3) demonstrating an improved cleaning efficiency.  A considerable increase in cleaning performance is shown for  cans 5 and 7 which each further include citrate and a non› ionic surfactant in the formulation. In addition, a significant  enhancement in cleaning performance was noted for can 6  which comprised treatment with polypropylene polymeric  particles and water only.  [0170]  The ingredients were Mulan™ 200S (25.0 g), a  non-ionic surfactant supplied by Christeyns, Bradford, UK  and the citrate component consisted of trisodium citrate dihy› drate (500.0 g) supplied by VWR, Loughborough, UK. The  polymeric particles were Nylon 6,6 grade Technyl™XA1493  supplied by Solvay, Lyon, France in the form of beads. The  mass of the polymeric particles used in the apparatus was 10  kg.  Uncoated  aluminum  metal  cans  grade  ALJSC60ML63X15 were supplied by Invopak UK Ltd.  Hyde, Cheshire.  [0171]  XPS analysis was carried out with an Axis Ultra  DLD, using an Al ka monochromated radiation source. An  overall survey scan was taken initially, followed by detailed  scans of the main peaks for the elements identified, using a  pass energy of 160 eV and 20 eV respectively. The measured  data was fitted using Casa XPS (Casa Software Ltd, UK),  using relative sensitivity factors based upon the scheme  where Cls=l, and adjusted to correct for any minor charging  using the aliphatic carbon peak at 285 eV. Each sample was  measured in 2 places.  [0172]  In order to carry out the experiments, the treatment  liquor was added to a vessel containing a pump. The treatment  liquor consisted of the polymeric particles (of total mass 10  kg) and tap water (45 kg) and the further formulation com› ponents as shown in Table 4. Aluminum cans were fixed to a  metal rod which was fixed by means of a clamp. Each can was  inserted into the vessel containing the treatment liquor. The  cans were then subjected to contact with the pumped liquor  for a period of30 minutes at a temperature of22°  C., ensuring  contact between the can and the treatment liquor. After treat› ment, the cans were washed with Milli-Q™ water and iso› propanol and subjected to XPS analysis.  [0169]  The data shown in Table 3 illustrates the results of  XPS analysis for the amount of aluminum oxide and alumi› num metal on the can surface following the various treat› ments (note that verified data for can 6 and can 7 was obtained  for cleaning efficiency only). The thickness of the aluminum  oxide layer was also calculated in accordance with the stan› dard methods outlined in B. R. Strohmeier, Surf. Interface  Anal. 1990, 15, 51 and T. A. Carlson, G. E. McGuire, J.  Electron Spectrosc. Relat. Phenom, 1972/73; 1, 161. As  shown by the results for can 5, treatment of the can with nylon  Sample Details and Formulation Components.  Sample  Can 1  Can 2  Can 3  Can4  Formulation components/treatment  Control Can - No Treatment  Can Treated With Water Only  Water 45 kg+ Citrate 500 g +  Non-ionic Surfactant 25 g  Water 45 kg+ Citrate 500 g +  Non-ionic Surfactant 25 g +  Nylon polymeric particles 10 kg  XPS results for aluminwn oxide removal  Aluminwn  Standard  Oxide  Deviation  Aluminwn Alwninum  layer  On Oxide/  Oxide  Metal  Thickness  Metal  Sample  Treatment  Area(%)  Area(%)  (nm)  Area(%)  Can 1  Control Can - 91.9  8.1  7.90  1.3  No  Treatment  Can 2  Water Only  95.4  4.6  9.51  3.1  Can 3  Water+  96.7  3.3  10.45  2.1  Citrate+  non-ionic  surfactant  Can4  Nylon+  92.9  7.1  8.28  3.3  Water  Can 5  Nylon+  80.6  19.4  5.36  1.2  Water+  Citrate+  non-ionic  surfactant  XPS results for cleaning efficiency  Alwninum  Metal  Carbon  Aluminum/  Content  Content  Carbon  Sample  Treatment  (%)  (%)  Ratio  Can4  Nylon+ Water  20.29  37.23  0.54  Can 5  Nylon+ Water+ Citrate+  31.38  27.96  1.12  non-ionic surfactant  Can 6  Polypropylene+ Water  23.49  33.23  0.71  Can 7  Polypropylene+ Water+  24.59  29.02  0.85  Citrate+ non-ionic  surfactant 