By the way, I am going to say that I have a problematic BTC address (or maybe a set of addresses) that concern me in terms of how it (they) was established and consolidated.. so still thinking about how to deal with some of my mistakes that were made.. and even hoping that there could be some ways to resolve some of my mistakes that were made.. but thinking and thinking.. without wanting to describe the particulars with too many details beyond just implying size and consolidation concerns.
You probably don't need help and will eventually figure this out, such as either ignoring the dust, or consolidating it all in one or a few transactions, loading up as many addresses or inputs as you can. But just in case, you can ask around here maybe someone knows what to do, or can do, or if its too much work or its possible.
If he isn't already using electrum he could export all the keys from his old wallets, then import them into electrum. After that he could freeze any problematic dust addresses, so they can't be spent from.
Either that, or wait until the fees are extremely low, then send dust spread across loads of addresses to a single consolidation address.
Fees are fairly low at the moment.
Today the bitcoinfees website says zero fee transactions can still confirm if you are prepared to wait 95 blocks.
It says a one sat per byte fee can confirm inbetween 3 to 64 blocks.
https://bitcoinfees.earn.com/*edit*Apparently it's very difficult to broadcast a zero fee transaction. There seems to be a way to trick electrum into letting you broadcast a zero fee segwit transaction, but I'm not sure if it works for normal transactions.
https://www.reddit.com/r/Electrum/comments/kt41dq/finally_changed_electrum_code_to_have_truly_zero/You can actually achieve this by using paytomany where you simply leave zero SAT for fees. I've done it in the past.
...it is very rare (5%) to find a node that will allow you to broadcast a zero fee TXN
If electrum won't let you generate a zero fee transaction you could try using an offline copy of coinb.in
https://coinb.in/#newTransactionYou can download it from the link at the bottom of this page.
https://coinb.in/#aboutThis is its bitcointalk thread.
https://bitcointalk.org/index.php?topic=390046*edit2*If he has an address with hundreds of dust inputs the thread below might offer a solution.
https://www.reddit.com/r/Electrum/comments/7qa45a/is_it_possible_to_specify_the_inputs_for_a_given/Any transaction with over a hundred inputs seems to create problems. Using electrum to create transactions with 50 inputs seems to solve this.
I hate to even say my problem.. but it is different than the one you are describing or suggesting in terms of dealing with dust or even a bunch of transactions that are combined.. but maybe I could just say if there were some combining of addresses on one occasion, and then moving that whole lump together at one point, then there are already two steps there, so it seems that it may be too late to do anything except maybe acknowledge them all as one owner. I am not really sure if I am currently wanting to attempt to resolve this, if there is even a resolution.