I forgot to mention that I have to check the compost first for insect and worm life!
Yes, few things are more shameful & annoying
than finding you've cooked a centipede - probably the best underground friend a gardener can have - high on the friends list with robins and ladybirds.
I spend several minutes picking through each batch of compost to be nuked, and in the process I also save a few friendly spiders and worms, but I've given up chasing the woodlice to where I can't see them.
I use a pair of 6 litre microwave pots (99p each from the 99p store) so I've always got some in reserve during a big job like potting up chitted aubergines, peppers & toms (I always nuke last year's stuff so 10-20 minutes on full power depending on how dodgy it looks). If you don't use it all then fungi will creep in - takes about 2 weeks but it can be re-nuked.
I usually include cockapoo pellets (poultry not dogs) in the batch - for greedy chits - doesn't smell and it doesn't seem to fungus any quicker.
OTOH Garden soil
will make the compost smell very strongly as it cooks - so if you use the kitchen microwave do everything in your power to keep garden soil (including John Innes) out. I found my personal MO in the street (gomi) but if it might have been rained on,
don't plug it in for at least a week or so.
I use readymeal containers too - but only for chitting - I nuke the whole
pre-seed package - nearly closed container with platform (bottom 8mm of damaged trays + flat section from damaged lids) and damp tissue all in place (if using kitchen roll pierce it down the midline or it will billow up - choose really rubbish stuff -
minimum wet-strength makes it easier to get the chits' roots out - the cheapest range in supermarkets is much worse [ie. better] than what's in the pound stores).
The best trays by far are the ones from City Kitchen - will last a lifetime (and the meals are better than most - though their Katsu curry hasn't been the same since they took the raw spring onion out - but just pop your own in and it's still good).
Cheers.
PS. In an emergency you can microwave damp (not sopping) stuff in a sturdy cardboard box - I've used well-shaken-out old washing powder boxes many times (cut down to fit upright through the door).