1346 The Cornell Reading-Courses 



coal, the stove lid should be left on. Many complaints of the warping 

 of aluminum have been due to not using this precaution. An aluminum 

 utensil may be injured by allowing some foods to remain in it for any length 

 of time. A story is told of how a family, summoned hastily away from 

 home, left oatmeal standing in an aluminum dish. When they returned 

 several days later, the dish was full of holes. The oatmeal had soured 

 with the heat, while some of the wild yeast plants always present in the air 

 had added themselves to the compound and begun to work, and in doing 

 so had riddled the utensil. 



The outside of aluminum utensils can be kept bright by the use of any 

 kind of metal polish that is not gritty. The inside surface is easily darkened 

 by water containing alkalies or iron. This thin dark coating is easily 

 removed by the use of whiting or any of the cleaning powders that do not 

 contain free alkali. If food or grease is burned into the surface, it can 

 usually be soaked loose by keeping hot water in the utensil for several 

 hours ; after which it may be removed by scraping with a wooden spoon. 

 If this fails, the utensil may be scoured with fine sand or powdered emery 

 or fine steel wool. If the utensil has been allowed to get into very bad 

 condition, one may have to use a solution of four tablespoonfuls of oxalic 

 acid crystals to a gallon of water in order to loosen the carbonized fat; 

 this solution to be left cold in the utensil overnight, or boiled in it for not 

 more than five minutes. Before using after this treatment, the utensil 

 should be washed carefully with hot water and soap. As oxalic acid is 

 very poisonous, every precaution should be taken. It is far better, if 

 the emergency requiring its use arises, to buy just enough instead of try- 

 ing to keep any on hand. The mild acid of sour milk or tart apples, boiled 

 in aluminum, will brighten it very effectually. 



Copper 



Copper is, next to silver, the best metallic conductor of heat. Its use 

 in the household is limited because of its expense and weight, the danger 

 from its use when not carefully cleaned, and the labor involved in keeping 

 it in good condition. This last point — which, in the mind of the house- 

 wife, condemns it utterly — is made an argument in its favor in many large 

 establishments, the theory being that one glance at a copper utensil will 

 reveal whether or not it is being properly cared for, thus economizing on 

 the time of a high-salaried inspector. Its durability also makes it desir- 

 able in public kitchens, where the time lost by having a utensil give out 

 is an item to be considered. 



Vegetables, acid fruits, or preserves, if cooked in copper, should not be 

 left for a moment after they are done. Copper and acid, when exposed 

 to the air, form verdigris, which we all know to be very poisonous. The 



