1. There is rust on the dining linen. After oxalic acid treatment, wash in the washing machine. After cleaning, it was found that the rust had not been removed. Acidification is the latter step in the laundry process. The quality of acid agents is crucial in laundry products. It can make up for the defects and deficiencies in previous processes, making the washing material perfect and reaching the ideal state. Oxalic acid is usually used in some laundry rooms, which is not enough. Calcium oxalate precipitation will form in unsoftened water and adsorb on the fabric, causing it to become gray, hard, and brittle.

用草酸除銹是不干凈的、暫時的。這種反應是可逆的，即Fe++（棕色）Fe++（淺綠色）。干燥后，織物上殘留的鐵被空氣氧化很長時間，然后變成鐵++。只有在草酸中加入其他酸性絡合劑，或使用其他除銹化合物形成穩定的絡合物或螯合物，才能將其去除。

Removing rust with oxalic acid is unclean and temporary. This reaction is reversible, i.e. Fe++(brown) Fe++(light green). After drying, the remaining iron on the fabric is oxidized by air for a long time and then turns into iron++. Only by adding other acidic complexing agents to oxalic acid or using other rust removal compounds to form stable complexes or chelates can it be removed.

2.在餐飲布草洗滌小方巾時，使用了洗衣專用美白粉、氯漂白粉和次氯酸鈉，但效果不佳。產生嚴重灰燼的原因如下：

2. When washing small square towels with catering linen, special laundry whitening powder, chlorine bleaching powder, and sodium hypochlorite were used, but the effect was not satisfactory. The causes of severe ash formation are as follows:

① 洗滌前，先了解洗滌方巾區域的水質特性，無論是軟水還是硬水。如果是硬水，就意味著鈣、鎂離子和金屬離子的含量很高。然后，清洗時必須添加軟水劑，后處理時必須使用中和劑。

① Before washing, first understand the water quality characteristics of the washing area, whether it is soft or hard water. If it is hard water, it means that the content of calcium, magnesium ions, and metal ions is high. Then, a softener must be added during cleaning, and a neutralizer must be used during post-processing.

② 洗滌毛巾時，應該同時使用氧氣漂白粉和洗衣粉。不要使用氯漂白粉，因為氯漂白粉具有高度氧化性，容易損壞毛巾。

② When washing towels, both oxygen bleach and laundry detergent should be used. Do not use chlorine bleach as it has high oxidation resistance and can easily damage towels.

③ 硬水可以產生鈣和鎂離子，形成鈣和鎂皂。鈣鎂皂本身就是一種污垢，俗稱皂垢或堿花。鈣鎂皂的殘余垢很難去除。如果長時間積累，會破壞纖維和色素，使衣服和棉織物變得稍硬，失去光澤，并改變色光。它對纖維非常有害，如脆性、斷裂、牢度降低等。鐵以離子或離子化合物的形式存在于水中。如果它沉積在織物上或變成棕色斑點，它會使白色織物整體變黃，使有色織物的顏色變暗，并對漂白有一定的催化作用。在嚴重情況下，還會導致織物損壞。。

③ Hard water can produce calcium and magnesium ions, forming calcium and magnesium soaps. Calcium magnesium soap itself is a type of dirt, commonly known as soap scale or alkaline flower. The residual scale of calcium magnesium soap is difficult to remove. If accumulated for a long time, it will damage fibers and pigments, making clothes and cotton fabrics slightly hard, losing luster, and changing the color and luster. It is very harmful to fibers, such as brittleness, breakage, and reduced fastness. Iron exists in water in the form of ions or ionic compounds. If it deposits on the fabric or turns into brown spots, it will cause the white fabric to turn yellow as a whole, darken the color of the colored fabric, and have a certain catalytic effect on bleaching. In severe cases, it can also cause fabric damage..

1） 從身體上尋找原因

1) Find the cause physically

① 洗衣服的時間太長了。餐飲布草毛巾在洗衣機中洗滌時，大部分時間都會不斷上下滾動，從而產生揉搓和摩擦運動。這種摩擦和摩擦運動是清潔毛巾的一個重要因素，因為臟毛巾不能僅通過浸泡在洗滌液中來清潔。這種摩擦不僅起到清潔毛巾的作用，還會磨損纖維，降低毛巾的牢固度。因此，控制合理的洗滌時間可以減少不必要的磨損，從而保證毛巾的正常洗滌壽命。

① The washing time is too long. When dining linen towels are washed in the washing machine, they will continuously roll up and down most of the time, resulting in rubbing and friction movements. This friction and frictional movement is an important factor in cleaning towels, as dirty towels cannot be cleaned solely by soaking them in detergent. This type of friction not only cleans the towel, but also abrades the fibers, reducing the firmness of the towel. Therefore, controlling a reasonable washing time can reduce unnecessary wear and ensure the normal washing life of towels.

② 脫水時多次高壓汽提速度過快，離心力過大會使毛巾棉纖維馬拉松，就像我們用手擰毛巾時用力過大，會使編織結構松動，導致毛巾中部或整個松散損壞，而正常損壞一般從邊緣開始。

② During dehydration, the high pressure steam extraction speed is too fast multiple times, and excessive centrifugal force can cause the cotton fibers of the towel to marathon. Just like when we use excessive force to twist the towel by hand, it can loosen the weaving structure and cause loose damage to the middle or entire part of the towel, while normal damage usually starts from the edge.