Wedding Dress Repairs

My granddaughter married in 2010. Her wedding dress,which she wants to keep forever, was hanging up with all the grubby stains and a few rips around the hems. As I am quite handy with the needle, she asked if I could just sew up a bit of the train. What I actually had to do (and am still doing) was, hang it over the bath to soak the bottom of all 7 skirt layers, scrub patches off the taffeta with soap and a soft nailbrush,( Not to be Dry Cleaned. Cold water and soap only.) Sew up several tears in the net, re- attach binding and so it goes..... I haven't finished yet , but I love her, so how could I say 'No.' Oh, and another thing, I'm having to do it with invisible thread, which is a pain to use.