Tufa Rock - Any 'preparation' Required?

I have low KH (3'd - ish) and low PH (varying around 6.0-6.8 ). I've just got some Tufa rock from a nearby aquatic shop where I bought some years ago. Apart from giving it a good scrub before I put it in the tank, is there anything else I ought to be doing? [Eg I only found out recently from other posts that I ought to have / could have boiled the wood that I put in the tank months ago, so if there's anything I else I should/could be doing with this rock, do let me know.] Thanks.

Thanks, Sue. [ I actually bought some of this rock years ago but it has been in the tank since - apart from a few months between goldfish-keeping and tropical fishkeeping when I was fishless    This new rock seems to have been bought into the aquatic shop recently but I'll give it a good scrub.  I'm assuming that the rock I bought before is the same as this, as it was bought for that purpose - but it seems to be completely hard whereas this new rock is soft and crumbly.].  I've been having a read around on the www for the past hour - some comments say that this shouldn't be used in soft water aquariums.  I have x-ray tetras and pygmy cories.  Hopefully they will be ok, even if I put a small piece in?

On a separate note, I had been wanting to clean my other, big 'cave'-like rock as it was getting a bit dirty.  I'd noticed on another forum that people use Milton and a toothbrush, so decided to try that.  I then had another hunt around on the www and found other posts that it could be toxic to aquatic life but others say that, if it's rinsed thoroughly and with dechlorinator too, it should be ok.  Any thoughts on this?  I'm a bit nervous about putting it back in now!

Thanks, Sue - that's reassuring. I've now rinsed it well, and it's in a bucket of water with dechlorinator, to stand overnight.

[I'll also bear in mind your illustrative use of dechlorinator, should I ever need that - useful household tip.]

As for the Tufa, it seems to have gone hard now.  I had broken off a small section which was soft and crumbly, but which has now hardened, and I reckon that such a small amount can't do any harm.  I can always put the bigger chunk in if it's making no difference to the KH and PH levels, and remove if these readings go too high.

Thanks, SteveS - and Sue - for the helpful advice and reassurances.