As long as you scrape most of the remnants out (and don't buy it in those stupid jars with shoulders which are apparently designed to retain as much as poss) you can clean them pretty well by filling with hot soapy water, leaving a for a good while and then giving a bloody good shake; and if you leave them for that while underwater, the labels come off too and can go in the paper recycling
. (In America peanut butter comes in jars the size of buckets, with straight sides, so it's easy to clean out and you only have to do it every few weeks.)
Ditto cooking oil bottles.
Re all the diff kinds of plastic, I had 2 long and (for them ) very tedious chats yesterday with local council recycling office & county council recycling centre. (The second one, obv getting a bit bored with my wittering, said kindly "don't worry about it" )
For recycling collection it's basically pop-type bottles (labelled PET with no. 1 in the triangle) and milk-type bottles (labelled HDPE with no. 2). Anything else, even if labelled PET (like strawberry cartons) mustn't go in, apparently because they sort it by floating and non-bottles are rejected (and probably then go into landfill )
However, if you have a friendly local recycling centre that takes all the random stuff like engine oil and batteries, it will also take all the other kinds of plastic and you don't even have to sort it first, they'll do that - so your meat trays, yogurt pots, takeaway trays, plastic packaging from eg shirts etc, in fact anything with the triangle on + any number from 3 up (the cap on a bottle of Tesco Pure fabric rinse has a 14 in it ), can all go there.
Also I just discovered that our paper recycling sack can take all our cardboard, which we used to take down to the recycling centre - the only thing they really don't like is jiffy bags.
I am working on having less landfill rubbish than anyone else in town!