The greening on the potatoes will not affect the quality of your compost and it will be quite safe to use on your allotment. What you will probably find is that these two potatoes will start to grow and you will get small or even large potatoes growing in the compost in the bin or allotment. Whilst still edible these potatoes can be a nuisance and a weed in the garden.

The bacteria and fungi in an active compost heap do an excellent job of digesting any organic poison, such as that in green potatoes. The poisons that you need to watch out for are the ones that don't digest. Those include heavy metals from the colored inks of some newspapers, arsenic from other inks and wood treated with some preservatives, and a few of the more long-lasting herbicides, such as prometone or polyborochlorates.

My hubby always microwaves any old potatoes to kill off the tubers etc before he puts them on the compost heap and that seems to work.

Thankyou so much for such a speedy response! Very reassuring and, as there's a wee frog sheltering in my compost bin at the moment, am glad I don't have to empty it all out.