As a novice at Sindy collecting who is learning the hard way, I feel I ought to help out people who are new to Sindy buying. I am in no way an expert and if the true experts know any better please help me out and let me know. I unfortunately have bought several "vintage" Sindys and am finding that investigation is key to getting what your after!
1. It is best if you can see the doll (naked) before you buy, so the more naked, clear photos there are the better. Then there are no hidden surprises (odd colour body, broken waist, pen marks, pin holes, nibbles etc when you take the clothes off to wash them once your purchase arrives!). Check Sindy for greenish colouring of the face or overly greasy looking skin (this can be hidden with talcum powder but the grease will come back and with vengance!), this could be a sign of chemical changes in the plastic.
2. Hips seem to suffer quite badly in Sindys, so check these especially for excess melted glue or chips of rubber off the tops, or loose elastic bands, resulting in swingy hips. Active sindys can fair quite badly with the years, so check them for loose body elastic (this can be fixed with a replacement band but involves popping the hip casing open which is extremely fiddly to repair and effectively damages the doll) wide split shoulder joints (inner shoulder hook separating from arm), lumps and bumps around arms and ankles may indicate repairs etc. Obviously this isnt as easy with boxed dolls, but Ive been told its a known fact that boxed dolls can sometimes have melt marks, this is an inevitable part of doll collecting and who wants to ruin an nrfb doll by taking it out of the packaging! My theory is, if it doesnt look like the ones you've seen in pictures it isnt nrfb or maybe its a special one off so does the price reflect this?
3. Ask questions if your unsure, a genuine seller shouldn't mind answering the odd question as it may help them gain a sale! Of course too many questions may get a little annoying.
4. Alot of people repair sindys from parts of others. This can be great if it is done properly, but unfortunately some people use parts that are from several different colour/age dolls, which creates a rather odd looking hybrid. So ensure all the separate parts (torso, bottom, arms, legs) are of similar colouring. There are a couple of great sites which give info on dating dolls bodies with pictures which may help, they come up on search engines under Sindy. They will give you a better idea about the origins of the doll you have, but unfortunately pedigree had a knack of making a few hybrid dolls of their own (previous years arms with new style body etc, etc) .
Having said all that I think that even the most hairless, pen marked, chewed and generally over-loved Sindy can become Fabulous with a bit of TLC.
Just to finish a few notes on cleaning:-
Start with baby wipes (the natural ones without lotion work best I find).
Try not to use water as it rots the elastic bands holding legs etc and rusts the screws in joint. If you really have to immerse it totally, shake off all excess then allow to dry naturally on a towel, not by a radiator.
Failing that try non acetone nail varnish remover, but very, very carefully using a bit at a time. Be aware it will remove face paint too! especially blush on cheeks.
I have been told that proper butter applied and left on a windowsill for a few days works wonders on pen marks, but I haven't dared try it as sunlight can cause chemical changes (discolouring) in some plastic leaving horrible permanent yellowing. I've been told there is something called oxy 10 which works wonders on pen marks, but again I havent dared try it.
I use baby shampoo on hair and then fragrance free fabric softner on mangled hair, combing through gently after conditioner (be very careful with a doll who has thinning plugs as combing could pull out the whole plug!), this works great with late 70's early 80's dolls, but 60's or early 70's dolls hair is different and you may not get the same results and your doll may require a re-root (this technique goes over my head and is very fiddly, so I wont attempt to explain methods, but there are a few re-root/ooak reviews on here telling you how). Do be careful how much fabric conditioner you use, especially with brunettes, it seems to fade their hair if you use alot and dont use it on a sindy horses mane, I tried it and its faded to a disturbing pink colour, lol.
Then (this is probably madness) but "mrs earle's" (the mail order one) superbalm to tame the frizzy ends, I suppose a fragrance free lip balm would work just as well.
Also bear in mind that older clothes arent colourfast like the more modern varieties, so exercise caution when washing. And lastly, dont wash an item with a black sindy label (these are rare as the label is made from paper, and it will disappear).
As Im becoming boring, and perhaps a little sad, lol, I better go now! Hope it helps.