Good move. Do it! It will work just fine, and no one will throw you out, probably not even people with No Solicitation signs (can't say I've ever seen one).
If it's not convenient to talk right there and then, make sure you have a large, sealed, envelope full of your persuasive sales material to leave with them, and try and follow up a few days later by phone. Just before you walk in, write on the envelope, addressing it to 'The Proprietor', 'The General Manager', 'The Managing Director' (or whatever seems appropriate for the business in question), followed by the business name.
If the person you talk to is obviously not one of these, don't start discussing your business, just ask them if they can pass your envelope to the correct person. (That's why the envelope must be sealed)
Sales is a numbers game. Cynics will say that people won't open your envelope, or they won't pass it on, or they won't talk to you, or they won't get back to you and - guess what - most of the time they're right!
But for sales we're not interested in 'most of the time', we're interested in the small number of people who ARE interested and who WILL buy, and we're not interested in anyone else.
So walk-ins are an quick and effective way of getting orders from small businesses.
It's not a perfect method, but there is NO perfect method.