How to clean or polish aluminum is the most often question asked by collectors.

      When I first started buying hammered aluminum it was often in a box of junk underneath a table at a flea market. That translates into there being a lot of dirt and scratches so upon returning home, the very first thing t I did was to squirt on some detergent and give the pieces a good warm water washing.  Generally, that was not enough to restore the hidden beauty of the motifs, so I used all that was available…my soap pads such as S.O.S.
     Sure, that left minute scratches, but the all over improvement was so remarkable that this remained my cleaning method for years. Remember, this was in the ‘70s!
     Now, thirty years later, this is not the recommended method and hasn’t been for years although a through washing is still the beginning.
     1. Wash and dry the piece.
     2. Rubber gloves are recommended from this point on!
     3. With a soft cloth apply a paste aluminum cleaner which              
          may be found in auto supply stores or sometimes in the                   auto supply section of stores such as Walmart.   a paste             cleaner named “Mothers” is the most often recommended.
     4. Rub the entire surface thoroughly with another cloth until             you have achieved the wished for finish.
     5. Repeat if necessary.
     6. Wash and dry thoroughly.

For scratches:
            1. depending upon the severity of the damage, use steel                                    wool, starting with the coarser and finishing with the                                    finest (oooo)
                2. Apply the Mothers cream  and follow instructions                                          above.
Badly pitted items cannot be restored although the appearance of a few can be diminished slightly. The same applies to deep scratches or cuts such as those caused by slicing cakes or pies.

I actually did this once on a piece with its appearance ruined by a deep scratch. It was an Arthur Armour piece I considered worth salvaging so I took a deep breath, got out some coarse sandpaper and went to work and eliminated the scratch but a horribly scratched area remained. I followed with the steel wool treatment, working down to the final polishing with Mothers. 

The piece was restored but this should never be attempted without practice on a uncared-for, worthless piece! NEVER!

If you do not wish your aluminum to have a bright shine and it had one when it was purchased, simply wait.  It will gradually become duller with the natural oxidation process.  Also, the bright shine created by all the hard work described above, will gradually dull. If you can live with that, let it be. If not, get out the rubber gloves and repeat the cleaning process.

Two more pieces of advice:
*Never wash Kennsington in a dishwasher.  It is not advisable to wash any of your hammered in your dishwasher although don’t panic if something gets slipped in occasionally.  The dishwasher detergents gradually dull the aluminum beyond restoration. My aluminum cooking vessels prove the point.

*Do not  attempt to remove the darkening around the motifs. Carefully removing grime is okay, but the darkening was done purposely to accent the pattern and once removed, the pattern/motif will not be as attractive.

Good Luck!