So i bought a couple of series 1, 1btc coins about a year and a half back and forgot about them..just checked them right now and the firstbits have gotten smudged 
..the coins are obvioulsy unopened)..i did write them down when i first got the coins..will this be a problem if i ever decide to sell them?
..the coins are obvioulsy unopened)..i did write them down when i first got the coins..will this be a problem if i ever decide to sell them?definitely. Collectors are asking about the condition of the coin and darkened brass (likely) or inreadable firstbits is definitely going to lower the price people are willing to pay.
EDIT: however, please note these coins already sell for 4 BTC or more (on forum) and/or USD 1.400 on ebay. So you got a good chance to make a huge profit when you sell them.