I have this problem here :(. This year I am doing a big clean up. I have been using a sledgehammer to break up bigger pieces of unwanted tufa and using in plant mixes or to line the bottom of pots instead of the usual crocks I used to use to improve drainage. Because I am growing so many acid loving plants I can not use this as much as I want though as it will change the pot acidity so I would be tempted to do this more if it was not so much of an issue. I also plan to make raised beds and use tufa as a base and top fill with soil.

When making big planters I throw in old tufa in between the mix but I only do this if the plant pot is 5cm thick or greater and this saves me using more mix then I would need to.

The key is to keep on top of all the waste more from the wrappers of cement sand bags etc...something which I have not done but will rectify this year hopefully

Not quite sure I understand. You want to know how to clean your molds and what to do with any leftover (wet) mix? If that's it, I clean the mold (mine are plastic) with a dish detergent (I use Dawn) and water. When I'm working on a project I keep empty egg cartons or other small molds handy. Any mix left over I put in the small molds and use them for "pot feet" or if there's enough, small planters. I dump the lime water on my lawn. I have gorgeous grass!

So it's okay to rinse the molds on the lawn? It won't hurt the grass and it actually improves it? I thought for sure it would kill the lawn. Please confirm that rinsing the molds on the lawn is actually a good thing for lawn.

It is a good thing if your lawn is acidic. I don't know your lawn so I can't "confirm". Google lime for lawns. You wipe out the excess mix and only rinse out the mold. You don't want to wash out near your well or waterway.

I have always rinsed mine on the lawn with no problem. We are in Ohio here, and our whole piece of the earth is one big lime deposit.

It shouldn't hurt, but if it worries you, rinse in a graveled drive or paved surface. And then water well to rinse and dilute any runoff.

I treat my pieces when they are finished curing (after about 10 days) with a diluted vinegar soak if they are small, or a diluted vinegar spray and repeat rinse if they are large.
I have not had any problems with alkalinity.

Hope this helps a little.

Here is a link that might be useful: The Hypertufa Gardener