I know that borer is forbidden on Shabbos but if certain conditions are met it may be okay. What are they?
In a nutshell the melachah of borer involves a mixture of “good” items (objects you intend to use or food you plan to eat) together with “bad” items (objects or foods you don’t intend to use or eat either because they aren’t good or because you have no interest in them at this time).
Selecting the bad items from the good items is considered borer. Selecting the good items from the bad ones is not considered borer and is permitted provided that the following two conditions are met: 1) The good items are selected immediately prior to the time you want to use or eat them; and 2) the good items are selected by hand (or a standard spoon or fork) as opposed to being selected by a utensil that is specifically used for selecting such as a sieve a slotted spoon or a sifter.
My toddler doesn’t like nuts in his salad. How can I pick them out for him?
You cannot remove the nuts since your toddler views the nuts as “bad” and selecting the bad from the good is considered borer even if you were to do so using your hands or immediately prior to feeding your toddler his salad. One solution to your predicament is that immediately prior to feeding your child you use your hands (or a fork) to remove pieces of salad from the bowl while leaving the nuts behind. Another solution is to pick out the nuts and pop them right into your own mouth.
Occasionally a fly gets into my drink. How can I remove it?
The accepted solution is to use a spoon to remove the fly together with some of the drink. (Preferably use a larger spoon so that more than a minimal amount of drink is removed.) This is not considered borer since the “bad” fly and (some of the) “good” drink have not been separated from each other; a selection did not take place. Alternatively lift and tilt the cup to allow some of the drink together with the fly to pour out of the cup.
