I respect all views on whether to clean or not to clean, but do not understand why "it is generally a bad idea to clean the antique uniform...". I would be grateful for some reasons therefor.
I have collected bullion badges and embroidered uniforms for 25 years. Before deciding on whether to clean or not, I examine the garment or badge in minutia, to determine, inter alia, the type and condition of the thread and the type and condition of the backing cloth. Poor quality bullion does not clean very well, and neither does very worn bullion which has been exposed to abrasion for a long time. In my experience old British, French and German bullion is of a high quality and I can normally successfully lift tarnish without damaging the thread.
Italian and US bullion need to be closely examined before deciding to clean, as it is sometimes of an inferior quality. I have found that the worst is Pakistani thread, which is generally of a very poor quality.
I generally take a conservative approach, and do not attempt cleaning if I believe that there is a significant risk of damage. Not only do I consider the bullion thread, but also the color and type of backing cloth and the condition of the cotton thread which is often used to hold the bullion in place.
I have tried just about everything that doesn't work, from metal polish to toothpaste, gold and silver dip, vinegar and gentle soap, and I have learned some hard lessons along the way. Nevertheless I have been able to achieve some very gratifying results.