Blitz Silver Polish http://www.ganoksin.com/gnkurl/ep80sk is one of
my all-time favorite polishes. It’s extremely mild (see my Silver
Polish Abrasion non-toxic, and inexpensive. It can be applied,
rinsed, then buffed, or applied, allowed to dry, then buffed. Blitz
will leave a decent tarnish-protective finish. I would recommend
giving a bottle of Blitz to any store carrying your silver and keep
some in the shop for yourself.
You should find any answers to your questions on The Care of Silver
And remind your customers that Tarn-X and other chemical dips will
allow tarnish to form much more quickly and eventually turn your work
a soft white. Acidified thiourea is NOT your friend.