Soiled clothing
A visible stain, ordinary dirt and religious impurity do not necessarily describe the same thing. Identifying the substance and affected area makes a question more precise. A manufacturer's washing instructions concern textile preservation; they are not, by themselves, a religious ruling on purification.
Practical checks: soiled clothing
To protect the fabric, first read its label and the cleaning product's precautions. Any concern about praying in that garment should be considered separately, stating known facts rather than assumptions. The religious resources provided can guide that enquiry but do not replace an answer suited to your circumstances.