I have only one sink. May I put metal racks in the sink, to be able to use it for Milching and Fleishig?
It is very difficult to have one sink and properly use it for Milichig and Fleishig. The best solution is to designate the sink for the use of the most common type in your kitchen (e.g. Fleishig) and purchase a sink insert for the other type (e.g. Milichig) use (or wash it in the laundry room, or some other similar approach)
When using the insert you should avoid using hot water which isYad Soledes Bo, if it drains straight out into the bottom sink.
if this option is not possible, you can use one sink provided that:
• You clean out the sink from residue to assure that when using Fleishig dishes no Milichig food particles get stuck to the dishes and they remain clean and when using Milichig dishes no Fleishig food particles get stuck to the dishes. Metal or any other material racks would work for this purpose as well.
• You never use hot water which is Yad Soledes Bo when washing dishes.
• You never let any dishes soak in the sink for 24 hours. (א)
• When pouring out hot liquid from a pot as when straining pasta it should be poured first into a second pot and then into the sink or wait until it cools down and it is not Yad Soledes Bo. (ב)
Sources:
א) בליעות מהכיור להכלים ע”י מים חמים. ויש בזה ג”כ דין כבוש כשנשארו שם מעת לעת – הכשרות א, ז.
ב) עיין יו”ד קה, ג ברמ”א. ויש שהביאו משוע”ר תנ”א, כא להקל אפילו לכתחילה. ועכ”פ כיון שרובא דרובא הוי זיעה ויס”ב כתבנו להחמיר לכתחילה.