Arranging the Music - what to do about the Vinyl (LPs)? part 2

Now some months later and my record cabinet still seems quite full.

Where to advertise? That is the first question! How to reach the collector that needs just one more copy?

It isn't obvious to me. I've tried Gumtree - which resulted in a few enquiries including a Famous Collector. And more recently Preloved.com which brought a bit more interest and another Serious Collector. Anyone hoping for fast movement will hope in vain.
 
A car boot sale is another option I've not tried. Does anyone have experience of this?

How to value them? This is the second important question! With some time and patience on the Internet is is possible to get a range of prices from dealers and private sales for the more wanted albums.

I wanted prospective purchasers to view the condition of the items they wanted, then go away with the list and make me an offer in writing later. This would give me the option to verify how reasonable their pricing was without too much pressure. However this is not the way they want to operate, and the collector is always at an advantage as they have been 'in the market' since they started collecting.

Actually with a couple of visits from collectors, some of the 'best' LPs have found new homes. And my wallet is a bit fatter. 50 or 60 records have been sold. Probably the remaining 250 will realise less than those already gone.