Hello, we are a very small janitorial service. We do a sweep, mop, and buff service on a small grocery store with VCT tile twice a week. It gets a strip and wax once a year and usually a scrub and recoat at the 6 month interval. During the winter the tile on the outer aisles and front and back gets yellowed. We attributed this to rock salt being tracked in. Last spring it was especially bad and when we did the strip it wouldn't come out. Finally after trying to restrip the worst aisle about 3 times and still ending up with very bad yellowing, we got some Comet and used it on the floor along with the side by side. It removed the yellow and made the tile look great again. We were very careful to rinse well and this looked good for about 6 months, then the owner went on an extended trip(2 months or more) and the employees were only spot mopping on the days we weren't there(they admitted this to us, and we don't think they were cleaning the mop either.). Now the tile looks worse then it did before and the problem is throughout the whole store, not just the outside aisles. My question is when we do strip, is it safe to use Comet on the whole store if we rinse well? Also should we use a neutralizer? Our other accounts also have VCT tile and they are on the same schedule and we don't have this problem with any of them, they all look fine. Any ideas will be will be appreciated, thanks!