import re
Input = "{1:A06YCASDB2LXXXXX000000}{2:A303TYDBTM2AXXD}{3:{108:23158}}{4:\r\n:20:APS0182405\r\n:23B:DRED\r\n:32A:182349USD3280,00\r\n:33B:USD31280,00\r\n:52M:/73240222\r\nRAWR UK Ltd\r\n28 School Road\r\nfast\r\nCo. Angrid\r\n:57A:TETRIS\r\n:59:/BU500023231012000066241\r\nDUMMYNAME DUMMYLASTNAME\r\PLACE/REST\r\n:70:PA74536/39\r\n:71A:OUR\r\n-} "
def chainRegex(string):                  
    x = re.sub(r"(?::\d{2}[A-Z]?:|\r\n)+", " ", string).split()
    return [w for w in ["".join(c for c in i if c.isalpha()) for i in x] if w != ""]
 
print(chainRegex(Input))
# ['AYCASDBLXXXXXATYDBTMAXXD', 'APS', 'DRED', 'USD', 'USD', 'RAWR', 'UK', 'Ltd', 'School', 'Road', 'fast', 'Co', 'Angrid', 'TETRIS', 'BU', 'DUMMYNAME', 'DUMMYLASTNAME', 'PLACEREST', 'PA', 'OUR']

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