Meaning, he should let a cook taste whether there is in it taste, as we established earlier in the beginning of siman 92 and 98, and such is written in the Beis Yosef. And the Rama goes according to his own reasoning, in that he writes in those places that we are not accustomed to rely on the tasting of a non-jew. Therefore he writes "And one needs to measure against the whole pot". And although it is implied in many places that that there is not in the volume of the amount contained in the utensil (the pot) sixty times the whole utensil (the walls and floor of the pot), one might answer that nevertheless, he is saying that one needs to measure it against the whole pot, and that therefore it will (always) be forbidden.

Alternatively, we find sometimes that the width of the pot is so big that it holds an amount of water that will be sixty times it (the walls and floor of the pot). For example if the copper (the material the pot is made of) is thin, but very wide, and like the Beis Yosef writes.

But in any case, this that we would need to measure (the contents of the pot) against the whole (walls and floor of the) pot, is by a used pot, that we don't know how much it has absorbed. But if we know how much it has absorbed, one need only measure against that amount that it had absorbed, as is said in 92:5 in the Rama, and in 94:6 and many places. And the same goes for when it was used, and we don't know how much was absorbed, but we know how much was cooked in it within 24 hours from the cooking of this milk, since what was cooked in it before 24 hours is nosein ta'am lifgam. And even if some meat was cooked in it within 24 hours of cooking the first meat, one does not need sixty times anything other than the second meat, and consider this.

AGAINST THE WHOLE POT: And later in Siman 98 he will explain that there is no difference between a pot of metal or of earthenware, one always needs to measure it against the whole pot, see there.

BUT THE POT IS FORBIDDEN TO COOK IN IT, NOT MEAT AND NOT MILK: Since it has absorbed both of them. Therefore, it is forbidden to cook meat in it from the outset (lechatchila) even after 24 hours from cooking now, the same way it is forbidden to cook milk from the outset in a pot of meat after 24 hours. However if he cooked meat in it WITHIN 24 hours of cooking milk in it, it's obvious that the food will be forbidden (even after the fact). But if he cooked milk it's obvious that it will be permitted after the fact.

However, other things that aren't of meat or of milk (pareve items), such as vegetables and fish and things like that, are permitted to cook in it even from the outset.

And later in 94:5 the Rama writes that the custom is to forbid a utensil that had been left for 24 hours even for other things (pareve), even when one had only dipped a spoon that had been used within 24 hours. If so, certainly (the custom applies) here where one cooked actual meat in it. We must explain that here he minced words regarding the halacha. And see what I wrote there in siman 94.

AND IT IS A STRINGENCY WITHOUT ANY REASON

Nevertheless, in Toras Chatos 85:4 he writes a bit of a reason according the ones stringent, which is that they hold that the prohibitions of steam (see 92:8) and smell (see 108) are stronger than that which is on account of taste itself. However Maharshal in his book of Issur Veheter siman 35 rejects another similar reason, and through his rejection rejects this reason as well, see there.

And he writes (quote) that it is only with those covers that are short (confined) on top, and which have in them something like a cavity as there is in many covers, and are therefore impossible to to clean well enough to be pure of any steaming or simmering that ascended there. But those that are wide (easily accessible) on top, and one's hand is able to reach in them to scrub them well, we do not say that there is physical issur (leftover), and it is permitted, end quote.

And according to his words we are forced to say that even though that which is in the confined space is a small amount (which should generally be batul beshishim), nevertheless the steam of the meat rises above (into that confined space) less than 60 times it, until it makes the physical amount (in the confined space) neveila, and subsequently the cover itself becomes neveila, as in 98:5, that there may not be 3660 times, minus a bit, the physical amount (in the confined space), and it is similar to what we said earlier in 92:5, see there.

But at any rate one definitely need not be so stringent when dealing with a cover, just as the Rama says here. And this is what is said in Aphei Ravrevei 61a, that in extenuating circumstances, or if there is any other reason to permit it, or if it is a wide cover, or if it is perforated on top, it would seem that one may permit it. And in addition, the Darchei Moshe screams bloody murder about this minhag, since it is a mistaken minhag, and it has no reason to explain it. And even the Ateres Zahav calls foul on this minhag.

If it starts to steam: And it would seem that it needs to be hot enough for the hand to avoid in the steam, and like we said earlier in 92:8 in the Rama.