Chess.com using the Glicko system (Google it) shouldn't really let your old record drag you that much. Your rating should be fairly accurate.
If you want to artificially increase your RD, making your rating more volatile, try not playing for a month. When you come back, your rating will change more drastically.
However, as I said before, I don't believe those old days are dragging down your rating. If you lost to a 1200 four years ago, that game probably has little influence over your current rating, read up on Glicko to understand why.
Okay I have been playing chess on chess.com for years now. The main area I play chess in is Blitz chess. I have accumulated over 5000 games in Blitz. I think I Have gotten a lot better in my last 2500 games than my first 2500 games.
My opponents have been stronger, my win record has been better in my last 2500 games. Are my older games dragging down my rating?
For example if a student got a C in the 1st half of the year in a class and then got an A in the 2nd half of the year in that same class his average would reflect a B even though the student has shown much improvement.
That is why I think the rating system sucks. It should only reflect your most recent 500 games or you can never escape a bad start.