against the spread of decay, the cleaning becomes practical and 

 desirable from the standpoint of marketing attractive fruit. 



Not all varieties of apples can be cleaned with equal f acility. In a 

 general way, practical experience as well as experimental results 

 have shown that the important apple varieties of the Pacific North- 

 west, when cleaned immediately after they have been picked, ranged 

 themselves about as follows in the order of difficulty of cleaning: 

 Esopus Spitzenburg, Arkansas Black, Yv r inesap, King David, De- 

 licious, Stayman Winesap, Jonathan, Yellow Newtown, Some Beauty, 

 and Winter Banana. The relative rank of different varieties with 

 reference to ease of cleaning has been about the same for washing as 

 for dry cleaning. 



In order to be commercially practicable from a cleaning-efficiency 

 standpoint, any type of equipment must have a considerable factor of 

 safety. By thi,s is meant that such equipment should be able to clean 

 fruit satisfactorily to the required tolerance, while operated at moder- 

 ate speeds and without the necessity for frequent repairs and adjust- 

 ments, and that it should do this with a minimum of rough handling 

 and mechanical damage to the fruit. A thorough study of cleaning 

 methods should be made before spray-residue removal is attempted. 



Decayed fruit should be sorted from sound fruit that is to be 

 cleaned by any method. It is obviously unwise to risk a heavy 

 contamination of the equipment by decay organisms. 



Considering the elements of cost, relative cleaning efficiency, han- 

 dling of the fruit, and tonnage capacity, it may be said that almost in- 

 variably the best dry-cleaning methods are neither so economical nor 

 so satisfactory as suitable washing methods. Where fruit is cleaned 

 primarily to improve its appearance, dry methods will be quite 

 satisfactory. 



CLEANING FRUIT BY WIPING OR BRUSHING 



The first commercial efforts to remove spray residue from apples 

 and pears were made with dry-cleaning methods. These seemed to 

 be the most simple and convenient and did not involve many changes 

 in the methods of handling the fruit. During the past two seasons 

 a comparative study has been made of the cleaning efficiency to be 

 obtained with the dry-cleaning equipment in commercial use in the 

 Pacific Northwest. The experimental results have been supplemented 

 by observations made under many different packing-house conditions 

 and covering practically all of the important varieties of apples and 

 pears. 



Special attention was devoted to four typical and relatively suc- 

 cessful dry cleaners herein described. 



DRY-CLEANING APPARATUS 

 REVOLVING-BRUSH CLEANER 



The fruit was carried along either on revolving brushes or upon a 

 narrow belt conveyor while the cleaning was done by brushes rapidly 

 revolving overhead in such a way that the bristle ends swept the 

 surface of the fruit. 



